Age of Onset, Current Use of Alcohol, Tobacco or Marijuana and Current Polysubstance Use Among Male and Female Mexican Students.

AIMS: This study aimed to examine alcohol, tobacco or marijuana use onset and associations between age of onset and current use, and between age of onset and current polysubstance use among a sample of Mexican young people aged 17-20 years. METHODS: Alcohol, tobacco, marijuana and other substance use were identified in a 2012 cross-sectional survey of male and female students entering first year university in Mexico City. Chi-square tests and logistic regression models examined associations between gender, age of onset, order of onset, family substance use and current polysubstance use among 22,224 students. RESULTS: The largest proportions of males and females initiated alcohol at age 15, tobacco at ages 15-16 and marijuana at ages 16-17. Earlier alcohol and tobacco initiation was associated with past 30-day use of the same substance. Gender differences in alcohol and tobacco use were small but males were significantly more likely than females to use marijuana and be polysubstance users. Family substance use was associated with earlier onset. There was a significant association between the earliest age of any of the three substances and current polysubstance use. CONCLUSIONS: A number of contextual and cultural factors in Mexico may be contributing to early onset, continued use and polysubstance use and deserve attention in research and by prevention programs.

Parental monitoring and family relations: associations with drinking patterns among male and female Mexican students.

INTRODUCTION: Parental monitoring and family relations are recognized as protective factors for youth alcohol use. The purpose of this study was to investigate perceived parental monitoring and family relations among subgroups of Mexican youths with different patterns of drinking behaviors and consequences. METHODS: A latent profile analysis (LPA) identified profiles of drinking behavior in a cross-sectional survey of entering first year university students. Multinomial regression examined associations between parental monitoring, family relations and drinking profiles among 22,224 students. RESULTS: Both lower perceived parental monitoring and weaker perceived family relations were associated with heavier drinking profiles among males and females, but more strongly associated with female than male heavier drinking profiles. Being older, having parents with lower education, and not living with parents were also associated with lower parental monitoring and weaker family relations. There was a general trend of lower parental monitoring and weaker family relations as the profiles increased from Non/Infrequent-No Consequences to Excessive-Many Consequences Drinkers. Lower perceived parental monitoring and weaker perceived family relations were more strongly associated with drinking profiles among females than among males. Both the parental monitoring and family relations scales had similar associations with drinking profiles. CONCLUSIONS: Findings suggest that drinking norms and values may contribute to any protective influences of parental monitoring and family relations on Mexican youths' drinking. Research about changes in drinking norms, contextual factors, and youth-parent trust would inform the utility of parental monitoring or family relations as protective strategies against alcohol misuse among Mexican and Mexican American youths and also youths from other backgrounds.

Natural mentors and youth drinking: a qualitative study of Mexican youths.

Parental influences on youth drinking are well documented but not the influence of extended family members. This article explores extended family influences on alcohol use among Mexican youths and whether extended family members can be considered natural mentors. We conducted a qualitative study using ethnographic open ended interviews with 117 first year university students in Mexico City. The ethnographic interviews revealed six drinking groups: excessive, heavy, regular, occasional, abstainers and non drinkers. Youths reported close relationships with extended family members who provided counsel and acted as representatives of familial norms and values. The alcohol beliefs and behaviors of these family members, including their alcohol misuse, had a positive influence on youths' alcohol attitudes. The naturally occurring mentoring relationships of Mexican extended family members can positively influence moderate youth drinking. Natural mentoring relationships should be encouraged and facilitated in prevention efforts for Mexican youths, Mexican-American youths and potentially other Hispanic/Latino youths.

Alcohol Use among Mexican Youths: Is Familismo Protective for Moderate Drinking?

The construct of familismo has been identified as a potential protective cultural value in Hispanic cultures. This paper considers familismo and alcohol use among young people in Mexico. We conducted a qualitative study using ethnographic open ended interviews with 117 first year students at a large free public university in Mexico City between April-May 2011. The findings indicate that dimensions of familismo can act as protective factors against misuse of alcohol among Mexican youths and may be protective for moderate drinking. Future research should explore the relationship of familismo to gender roles and other cultural values during adolescence. Given the enduring influence of Mexican cultural values among Mexican Americans the research has implications for prevention programs for both Mexican and Mexican American youths.

Changes in alcohol use among first year university students in Mexico.

BACKGROUND: Alcohol use and misuse is widespread among university students in many countries. Specific cultural factors may impact alcohol use after entering university. OBJECTIVE: This paper considers changes in alcohol use among first year university students in Mexico. METHODS: A qualitative study using ethnographic interviews with 57 female and 60 male student drinkers in Mexico City from March to June 2011. Each interview was evaluated by a set of thematic codes developed inductively from the interviews. Findings from excessive, heavy, regular, occasional drinkers, abstainers, and non-drinkers were analyzed to explore whether or not linkages existed between and/or among particular themes. RESULTS: Students reported factors associated with changes in role and status, friendships, and increased autonomy as reasons for increasing or decreasing their alcohol use after entering university. CONCLUSIONS/IMPORTANCE: Understanding the influence of Mexican cultural norms on alcohol use among Mexican and Mexican Americans can be helpful in informing studies and preventive efforts among both Mexican and Mexican American young people.

Drinking patterns and victimization among male and female students in Mexico.

AIMS: The purpose of this study is to estimate the prevalence of alcohol use and alcohol-related consequences, identify drinking profiles using latent profile analysis (LPA), and investigate associations between profiles and violent victimization among young people in Mexico. METHODS: LPA identified profiles of drinking behavior in a survey of entering first year university students. Multinomial and logistic regression examined associations between drinking patterns, socio-demographic variables and violent victimization. RESULTS: The LPA identified five profiles of behaviors and consequences among the 22,224 current, former and never drinkers: Non/Infrequent-No Consequences, Occasional-Few Consequences, Regular-Some Consequences, Heavy-Many Consequences and Excessive-Many Consequences drinkers. The Occasional-Few Consequences profile comprised the largest, and the Excessive-Many Consequences profile the smallest, group of drinkers. Multinomial regression showed males and older students more likely to be Heavy or Excessive-Many Consequences drinkers. Living alone was associated with higher odds, and higher maternal education with lower odds, of being a Non/Infrequent-No Consequences drinker. Heavier drinking profiles were more likely to experience violent victimization adverse consequences. Logistic regression showed male and female Heavy and Excessive-Many Consequences drinkers had the highest odds, and Non/Infrequent drinkers the lowest odds, of experiencing any victimization. CONCLUSION: Findings suggest changes in male and female drinking behavior and a continuation of the established pattern of infrequent but high consumption among Mexican youths. Both male and female Heavy and Excessive-Many Consequences drinkers were at elevated risk for experiencing victimization. Identifying cultural gender norms about drinking including drinker expectations and drinking context that contribute to these patterns can inform prevention efforts.

Contribución genética, ambiental y epigenética en la susceptibilidad a los trastornos del espectro autista / Genetic, environmental, and epigenetic contribution to the susceptibility to autism spectrum disorders

Introducción. Los trastornos del espectro autista (TEA) son condiciones neuropsiquiátricas comunes y complejas en las que están involucrados diversos factores. Objetivo. Revisar el conocimiento actual sobre los posibles factores de riesgo para los TEA.Desarrollo. Se investigó sobre factores potenciales de riesgo para los TEA, y se recabó información sobre trastornos y genes en las bases de datos de Medline, OMIM y Ensembl. Conclusiones. En los TEA se presenta una notoria heterogeneidad genética y probablemente distintos modos de transmisión. Además, muchos casos se asocian con mutaciones de novo o con alelos raros con un efecto probablemente importante. La heredabilidad en estos trastornos puede ser menor a la estimada anteriormente. Una fracción de ésta puede ser explicada por alelos relativamente comunes con un efecto débil. El ambiente perinatal y posnatal, la epigenética, la edad del padre y, posiblemente, la de los abuelos varones cuando nacieron sus respectivos hijos son relevantes en los TEA. Estosúltimos podrían relacionarse con el desarrollo y la conectividad de las sinapsis, la neurotransmisión, la señalización, la neuroplasticidad y la expresión genética. Diversos tipos de estudios han contribuido a entender la etiología de los TEA. Los estudios de enlace genético y asociación no son apropiados cuando hay mutaciones nuevas con efecto importante. Finalmente, el incremento en la prevalencia de los TEA podría deberse a una mayor conciencia sobre los trastornos, a cambios en los criterios diagnósticos y exposiciones ambientales, a modificaciones epigenéticas y a un número creciente de mutaciones de novo que incrementan el riesgo a los trastornos (AU)

Introduction. Autism spectrum disorders (ASD) are common and complex neuropsychiatric disorders in which multiple factors may contribute to the phenotype. Aim. To review current knowledge about possible risk factors for ASD. Development. Medline, OMIM and Ensembl databases were searched for possible risk factors, disease and gene information. Conclusions. There is genetic heterogeneity and probably different modes of transmission in ASD. In addition, many cases are related with non-inherited de novo mutations or uncommon alleles with a large effect. The general heritability in these disorders may be lower than previously reported. Some fraction of it may be explained by relatively common alleles that tend to have a small effect. To some extent, susceptibility alleles may have a different influence on the phenotype depending on other genetic or non-genetic factors. Non-genetic factors in the perinatal and postnatal period, including epigenetics, the age of the father and possibly the age of grandparents at conception may be relevant for ASD. The mechanisms involved in the etiology of ASD may be related with synaptic development and connectivity, neurotransmission, signaling, neuroplasticity, and gene expression. Different methods have contributed to understand the etiology of ASD. Linkage and association studies are not appropriate for ASD cases with de novo mutations with a strong effect. The observed increase in ASD prevalence may be related not only with more awareness, changing diagnostic criteria, and environmental exposures, but also with epigenetic changes, and an increasing number of de novo mutations. (AU)

[Genetic, environmental, and epigenetic contribution to the susceptibility to autism spectrum disorders]. / Contribucion genetica, ambiental y epigenetica en la susceptibilidad a los trastornos del espectro autista.

INTRODUCTION: Autism spectrum disorders (ASD) are common and complex neuropsychiatric disorders in which multiple factors may contribute to the phenotype. AIM: To review current knowledge about possible risk factors for ASD. DEVELOPMENT: Medline, OMIM and Ensembl databases were searched for possible risk factors, disease and gene information. CONCLUSIONS: There is genetic heterogeneity and probably different modes of transmission in ASD. In addition, many cases are related with non-inherited de novo mutations or uncommon alleles with a large effect. The general heritability in these disorders may be lower than previously reported. Some fraction of it may be explained by relatively common alleles that tend to have a small effect. To some extent, susceptibility alleles may have a different influence on the phenotype depending on other genetic or non-genetic factors. Non-genetic factors in the perinatal and postnatal period, including epigenetics, the age of the father and possibly the age of grandparents at conception may be relevant for ASD. The mechanisms involved in the etiology of ASD may be related with synaptic development and connectivity, neurotransmission, signaling, neuroplasticity, and gene expression. Different methods have contributed to understand the etiology of ASD. Linkage and association studies are not appropriate for ASD cases with de novo mutations with a strong effect. The observed increase in ASD prevalence may be related not only with more awareness, changing diagnostic criteria, and environmental exposures, but also with epigenetic changes, and an increasing number of de novo mutations.

TITLE: Contribucion genetica, ambiental y epigenetica en la susceptibilidad a los trastornos del espectro autista.Introduccion. Los trastornos del espectro autista (TEA) son condiciones neuropsiquiatricas comunes y complejas en las que estan involucrados diversos factores. Objetivo. Revisar el conocimiento actual sobre los posibles factores de riesgo para los TEA. Desarrollo. Se investigo sobre factores potenciales de riesgo para los TEA, y se recabo informacion sobre trastornos y genes en las bases de datos de Medline, OMIM y Ensembl. Conclusiones. En los TEA se presenta una notoria heterogeneidad genetica y probablemente distintos modos de transmision. Ademas, muchos casos se asocian con mutaciones de novo o con alelos raros con un efecto probablemente importante. La heredabilidad en estos trastornos puede ser menor a la estimada anteriormente. Una fraccion de esta puede ser explicada por alelos relativamente comunes con un efecto debil. El ambiente perinatal y posnatal, la epigenetica, la edad del padre y, posiblemente, la de los abuelos varones cuando nacieron sus respectivos hijos son relevantes en los TEA. Estos ultimos podrian relacionarse con el desarrollo y la conectividad de las sinapsis, la neurotransmision, la señalizacion, la neuroplasticidad y la expresion genetica. Diversos tipos de estudios han contribuido a entender la etiologia de los TEA. Los estudios de enlace genetico y asociacion no son apropiados cuando hay mutaciones nuevas con efecto importante. Finalmente, el incremento en la prevalencia de los TEA podria deberse a una mayor conciencia sobre los trastornos, a cambios en los criterios diagnosticos y exposiciones ambientales, a modificaciones epigeneticas y a un numero creciente de mutaciones de novo que incrementan el riesgo a los trastornos.

Parental monitoring and alcohol use among Mexican students.

Parental monitoring has been described as a protective factor and useful strategy to prevent substance misuse among youths. The aim of this study was to examine whether perceived parental monitoring influences frequency of alcohol use, age of drinking onset and risky drinking among entering public high school and university students in Mexico City. The study is a cross-sectional survey of entering first year students in the high school and university school system of a large public university in Mexico City conducted during registration at the beginning of the school year. In 2008, of 34,840 students accepted to the affiliated high schools, 28,996 students (51.8% female) completed the alcohol survey and of 37,683 students accepted into university 30,084 students (51.5% female) completed the alcohol survey. The findings suggest that compared to students with higher perceived parental monitoring those reporting lower perceived parental monitoring were more likely to report risky behavior. They were more likely to be ever drinkers, frequent drinkers, have earlier age of onset and high AUDIT scores. Overall, higher parental monitoring was strongly associated with being female and lower parental monitoring with being male. Our findings suggest that more research on parental monitoring as a protective strategy against alcohol misuse is needed. Research focusing on cultural factors including gender and age-related norms and familismo would increase knowledge of the association of parental monitoring and alcohol use among Mexican youths, Mexican American youths and potentially youths from other Hispanic backgrounds.

Eficacia de un programa de intervenciones terapéuticas en estudiantes universitarios diagnosticados con dependencia al alcohol / Efficacy of a therapeutic intervention program among Mexican college students diagnosed with alcohol dependence

In recent years, consumption of alcoholic beverages has become a common practice among young adults attending higher education institutions in Mexico. Over the past two decades, prevalence of alcohol consumption in this population has doubled. In campuses located in Mexico City, 70-90% of undergraduate students have consumed alcoholic beverages during the past year and approximately 25% have engaged in binge drinking. Past year prevalence of Alcohol Dependence (AD) has been estimated in 4.6% and 18.4%. Higher education institutions around the world have implemented programs aimed at reducing students' drinking that have included educational interventions and/or psychosocial treatments delivered individually or in group format. In this regard, the available evidence suggests that programs that have included elements of the Motivational Enhancement Therapy (MET) or components of the Cognitive Behavioral Therapy (CBT) have shown the greatest efficacy in reducing drinking problems in this population. Despite this, there are no studies examining the efficacy of these interventions in Mexico's college student population. In the report presented here, we aim at examining the efficacy of Individual or Group MET and CBT in reducing drinking among undergraduate students diagnosed with AD. We hypothesized that in comparison to CBT, MET would show evidence of a greater reduction in alcohol consumption. To evaluate this hypothesis we examined the treatment effects on the number of consumed drinks, on the number of drinking days, and on the number of drinks per drinking day during the preceding 30 days. Methods We prospectively evaluated during an 8-week treatment phase and during a 12-month follow-up period, 158 undergraduate students who received a diagnosis of AD (ICD-10) at the students' Mental Health and Counseling Center of the National Autonomous University of Mexico (UNAM) in Mexico City. Instruments. In order to screen and to establish the diagnosis of AD we respectively used the Alcohol Use Disorders Identification Test (AUDIT) Mexican version and the Composite International Diagnostic Interview (CIDI). We also used The Alcohol Time line Followback (TLFB) method to retrospectively record the amount and frequency of alcohol consumption. Procedures. Students seeking services at the UNAM Mental Health and Counseling Center, and who had a diagnosis of AD, were invited to participate in the study. After informed consent was obtained, they were randomly assigned to one of four manualized treatment interventions: Individual or Group MET, or Individual or Group CBT. These were delivered in eight weekly sessions lasting one hour. The alcohol TLFB was administered at the beginning and at the end of the 8-week treatment phase, and subsequently monthly for the following 12 months. Statistical analysis. An analysis of variance (ANOVA) for repeated measures was used to examine the treatment effect on drinking during the treatment phase and separately during the 12-month follow-up period. A one-way ANOVA was used to examine differences between treatment groups at specific assessment points. Results Demographic characteristics. In the entire sample the majority of students were men (73.2%), while the mean age was 18.8 [± 2.9] years. There were no differences between intervention groups in their demographic characteristics. Baseline characteristics of alcohol consumption. In the entire sample and separately in each of the intervention groups there was a predominant pattern of weekly heavy drinking. There were no baseline differences between treatment groups in the monthly amount or frequency of drinking, or in the number of drinks consumed during drinking days (all comparisons P>0.50). The average number of Alcohol Dependence symptoms was 6.0 [± 2.6]. There were no differences among groups in the number of these symptoms (P=0.10). Patient Retention during the Treatment Phase and the Follow-up Period. At the end of the 8-week treatment phase, 92% of the students remained in treatment. During this phase, the Individual CBT group had the greatest number of dropouts with 18% of them leaving prematurely (Pearson X² = 15.7, df=3, P = 0.001). During the follow-up period, specifically at the 3, 6 and 12-month follow-up, the retention rates in the study were respectively 91%, 89% and 86%. There were no differences among groups in this variable at any of these follow up points. Alcohol consumption during the treatment phase. In the ANOVA for repeated measures we found that during the treatment phase there was a main effect of time over the three indicators of alcohol consumption (range of F: 7.59-11.81, df=1.142, range of P:0.001-0.007). This reflected the fact that at the end of the four interventions there was a reduction in the amount and frequency of monthly drinking and a reduction in the number of drinks during drinking days. There were no main effects of treatment (range of P:0.07- 0.56) or interactive time X treatment effects (range of P:0.55 to 0.79) on any of the drinking variables. However, at the level of a non-significant trend (F = 2.37, df=3.143, P = 0.07), there was a treatment effect reflecting that in comparison to Individual CBT, there was a trend toward a greater reduction in the frequency of monthly drinking in Group MET (one-way ANOVA: F=2.60, df=3.146, P=0.05, Tukey HSD P=0.07). Alcohol consumption during the follow-up period. In the ANOVA for repeated measures, there was a main effect of time on the amount and frequency of monthly alcohol consumption (range of F: 8.54-9.53, df=3.393, P range: 0.001-0.004), reflecting that during this period there was a reduction in these two drinking variables in the entire sample. This effect was observed mainly during the first six months of follow-up. During the following six months, there was a gradual increase in the amount and frequency of drinking (range of F for the quadratic component of Time: 5.36-10.36, df=1.131, range of P: 0.02-0.002) that approached the levels seen at the end of treatment. There were no main effects of time on the number of drinks consumed during drinking days (P=0.27). There was a treatment X time interaction (F=2.65, df=3.131, P=0.05) on monthly frequency of drinking, indicating that, in comparison to Individual CBT, there was a greater reduction in this drinking variable in Group MET. This effect was specifically observed during the first three months of follow-up (one-way ANOVA: F=3.63, df=3.142, P=0.02, Tukey HSD P=0.007). Subsequently, there were no differences among the intervention groups in this variable for the remaining nine months of follow-up. Finally, there were no main effects attributable to treatment or interactive effects of time X treatment on the number of monthly drinks (P range: 0.49 to 0.65) or on the number of drinks consumed per drinking day (P range: 0.55 to 0.79). Discussion In this sample of alcohol dependent college students, we found that at the end of the 8-week treatment phase there was a comparable reduction in the amount and frequency of alcohol consumption and in the number of drinks consumed during drinking days across the four intervention groups. However, we observed that at the level of a non significant trend (P=0.07), Group MET appeared to be more effective than Individual CBT in reducing the frequency of alcohol drinking.

Introducción Se ha descrito que entre los estudiantes de educación superior de nuestro país la prevalencia del consumo de alcohol se ha duplicado durante las últimas dos décadas. Se han estimado prevalencias durante los últimos 12 meses del diagnóstico de Dependencia al Alcohol (DA) de 4.6%. Aunque se desconoce la magnitud de las consecuencias de estos problemas entre los estudiantes universitarios mexicanos, en Estados Unidos han sido identificados como un problema de salud pública mayor y como el principal problema de salud en las universidades. Para reducir estos problemas, se ha evidenciado que las intervenciones como la Terapia de Incremento de la Motivación (TM) o la Terapia Cognitivo Conductual (TCC) podrían ser igualmente efectivas a largo plazo. Se ha observado una ligera ventaja del formato individual sobre el grupal. Pero al analizar el costo-beneficio, el formato grupal suele ser el más utilizado en las universidades. A pesar de la importancia de los problemas por consumo de alcohol en las universidades y no obstante la efectividad demostrada de estas intervenciones, no hay, hasta lo que sabemos, investigaciones publicadas que comparen la eficacia de la TM y la TCC en el tratamiento de los universitarios con problemas por consumo de alcohol en México o en otros países de habla hispana. Objetivo Examinar los efectos de las intervenciones TM y TCC tanto en su modalidad individual como grupal, en el tratamiento de estudiantes universitarios con diagnóstico de dependencia al alcohol. Material y métodos Se evaluó prospectiva y comparativamente a 158 estudiantes universitarios con diagnóstico de Dependencia al Alcohol. Instrumentos: 1. Alcohol Use Disorders Identification Test (AUDIT); 2. Composite International Diagnostic Interview (CIDI); 3. Línea Base Retrospectiva (LIBARE); 4. Cuestionario de Datos Demográficos. Procedimientos. A los estudiantes con problemas con su manera de beber, se les aplicó el AUDIT; a los que tuvieran respuestas positivas para Dependencia al Alcohol, se les aplicó la sección de <

The complex interplay of genetics, epigenetics, and environment in the predisposition to alcohol dependence / La compleja interacción genética, epigenética y ambiental en la predisposición a la dependencia al alcohol

Alcohol dependence is a major global problem, associated with lower quality of physical and mental health, higher mortality and an enormous familial and social cost. Prevention strategies and treatment of this condition are therefore crucial. Success of psychosocial programs and pharmacological treatments has been frequently reported, but a better understanding of the etiology of this chronic disease is needed. For this purpose, the identification of associated factors in different populations is of great significance. It has been clearly demonstrated by twin and adoption studies and supported by animal models that both genetic and environmental components play a substancial role in alcohol dependence. Heritabil ity estimates range from 40 to 60%, depending on the specific analyzed sample. Several coexisting genetic variants in each affected individual, rather than a single gene transmitted in a Mendelian manner, may be the rule in alcohol dependence. Similarly, many environmental factors can increase susceptibility, and because of their diversity, they do not have to be the same in every affected person. Environmental contribution may be linked to epigenetics, which refers to chemical processes that can modify gene activity without changing the sequence of DNA. In humans, the most stable epigenetic process is the union of a methyl group (one carbon atom surrounded by three hydrogen atoms) to cytosines in DNA. Other epigenetic mechanisms are modifications to nuclear proteins called histones, which alter the way DNA is packed. Moreover, non-protein coding RNAs such as microRNAs have been associated with the development of alcohol dependence. MicroRNAs could work as epigenetic intermediaries that allow ethanol to affect complex and divergent developmental mechanisms, which is added to the effect of DNA methylation, histone acetylation, and other epigenetic modifications. Most reasearch points to an association between alcohol dependence and genes related with alcohol metabolism, with neurotransmission of dopamine, GABA, serotonin, glutamate, endogenous opioids, and cannabinoids, signal transduction within the mesolimbic dopamine reward system, and stress response system, among others. During pregnancy, there are several non-genetic factors that may have an important impact on vulnerability to alcohol dependence. Given that the Central Nervous System is developing throughout the entire pregnancy and that alcohol consumed by the mother can reach the fetus through the placental barrier, the brain of a baby is always vulnerable to harm caused by alcohol exposure. Children born to alcoholic mothers may inherit genetic susceptibility variants but at the same time they may be exposed to early effects of ethanol. Heavy alcohol exposure during pregnancy has been associated with mental retardation, epilepsy, attention deficit/ hyperactivity disorder, learning disabilities, and later on with substance abuse, anxiety, personality, affective and psychotic disorders, as well as with engagement in antisocial behaviors and school or work problems. Furthermore, it has been shown that animals exposed to prenatal stress exhibit persisting modifications related to dopamine and glutamate transmission in limbic structures associated with dependence to alcohol and other substances. These alterations may later contribute to increase motivation to drink, to use large amounts of drugs of abuse or to relapse after periods of drug withdrawal. It was shown that after exposure to prenatal stress, male mice consumed more ethanol during alcohol reinforcement in adulthood. In addition, it has been well documented that affective disorders are associated with alcohol dependence. A recent meta-analysis including 54 studies that together involved more than 40749 individuals, confirmed that the 5-HTTLPR polymorphism at the promoter of the serotonin transporter gene moderates the association between stress and depression, where the short allele is related with an increased risk for depression under stress (p = 0.00002). A strong association was detected when the stressful factor was childhood maltreatment (p = 0.00007). Childhood maltreatment, including neglect as well as physical and sexual abuse, is associated with developmental difficulties, low social competence and self-esteem, and it is an important risk factor for binge drinking in adolescence and alcohol dependence in adulthood. Childhood maltreatment may interact with factors such as variants of the monoamine oxidase-A and catechol-o-methyltransferase gene. Adolescence is a critical period for initiation of alcohol intake, experimentation, and establishment of regular drinking patterns. Substance use at this age is considered a risk factor for the development of later alcohol and other drug-related problems, as well as for externalizing disorders such as antisocial personality disorder. Alcohol use initiation is affected by environmental factors such as ethanol availability, parental attitudes, and peer pressure. It has been reported that heavy drinking during adolescence can have a negative impact on brain development. Moreover, dopaminergic and GABAergic systems undergo important changes during adolescence, and they can be affected by alcohol intake. Dopamine is implicated in the rewarding effects of ethanol, and GABA in its sedating effects and development of tolerance. The way an adult copes with environmental challenges is notably influenced by early life experiences and by the familial environment he or she had as an infant, which affects neurodevelopmental behavior. While environmental factors tend to have a crucial role in drinking habits in adolescence, adultood may be characterized by a weaker effect of environment and a higher effect of genetic components. It is probable that a complex set of gene-environment interactions determine the risk to alcohol dependence. Environmental factors that may affect this vulnerability appear at different stages from pregnancy to adulthood. These interactions are mediated by DNA methylation, histone modifications, protein complexes and non-protein-coding RNAs such as microRNAs.

La dependencia al alcohol es un problema mundial grave, que se asocia con mucho sufrimiento, problemas de salud mental y física, una elevada tasa de mortalidad y un costo social y familiar muy alto. Es por esto que las estrategias de prevención y el tratamiento de la enfermedad resultan cruciales. Se ha reportado que programas psicosociales y tratamientos farmacológicos son hasta cierto punto exitosos actualmente. Sin embargo, se requiere conocer más profundamente la etiología de la enfermedad. Por esta razón, es muy importante identificar los factores que se asocien con el incremento a la susceptibilidad en distintas poblaciones. Se ha demostrado claramente a través de estudios en gemelos y de adopción, así como por investigaciones en animales, que tanto factores genéticos como ambientales son relevantes en la dependencia al alcohol. Se ha estimado que la heredabilidad de esta enfermedad se encuentra entre 40 y 60%, dependiendo de la muestra estudiada, lo cual indica que el ambiente y la genética tienen un peso similar en la susceptibilidad. Muchas variantes genéticas que aumentan la susceptibilidad, en lugar de una sola, podrían coexistir en las personas más vulnerables a la dependencia. De manera similar, muchos factores ambientales parecen estar relacionados, los cuales, debido a su diversidad, intensidad y etapas de la vida en la que se presentan, no son exactamente iguales en diferentes personas con dependencia al etanol. La contribución ambiental podría relacionarse con cambios en la expresión de genes, lo cual involucra a la epigenética. Ésta se encarga del estudio de los procesos químicos, afectados por el ambiente, que pueden modificar la actividad de los genes sin cambiar la secuencia del ADN. En humanos, el proceso epigenético más estable es la unión de un grupo metilo (un átomo de carbón unido a tres átomos de hidrógeno) a las citosinas en el ADN. Otros mecanismos epigenéticos son modificaciones a proteínas nucleares llamadas histonas, proceso que modifica la manera en que se encuentra empaquetado el ADN. Por otra parte, ARNs que no codifican para proteína, como los microARNs, se han asociado al desarrollo de la dependencia al alcohol. Ciertos microARNs podrían funcionar como intermediarios epigenéticos, lo cual propiciaría que el etanol afectara procesos complejos y divergentes del neurodesarrollo, sumándose al efecto de la mutilación en el ADN y de la acetilación de histonas, entre otros procesos epigenéticos. La mayoría de las investigaciones señalan que los genes importantes en la vulnerabilidad a la dependencia al alcohol incluyen algunos que codifican para proteínas del metabolismo del alcohol; de neurotransmisión de dopamina, GABA, serotonina, glutamato, opiodes endógenos y canabinoides; de transducción de señal en el sistema de recompensa mosolímbico; y de respuesta al estrés, entre otros. Durante el embarazo, diversos factores no genéticos tienen un impacto importante en la vulnerabilidad a la dependencia al alcohol. Por ejemplo, debido a que el Sistema Nervioso se desarrolla a lo largo de toda la gestación y que el alcohol consumido por la madre puede llegar al feto a través de la barrera placentaria, el cerebro de un feto siempre es vulnerable al daño provocado por la exposición al etanol. Se ha demostrado que los hijos de mujeres alcohólicas no sólo pueden heredar variantes genéticas de riesgo sino que también pueden estar expuestos tempranamente a los efectos del alcohol consumido por sus madres. El consumo excesivo en el embarazo se ha asociado con retraso mental, epilepsia, déficit de atención/ hiperactividad, problemas de aprendizaje, y más adelante con abuso de sutancias, ansiedad y trastornos afectivos, de personalidad y psicóticos, así como con conductas antisociales y problemas en la escuela o el trabajo. Además, se ha demostrado que animales expuestos a estrés prenatal mostraban modificaciones persistentes relacionadas con la transmisión dopaminérgica y GABAérgica en estructuras límbicas que se relacionan con dependencia al alcohol y a otras drogas. Más adelante, estas alteraciones podrían contribuir a la motivación para beber, a utilizar mayores cantidades de alcohol u otras susancias de abuso o a la recaída después de periodos de abstinencia. Se encontró que ratones macho expuestos a estrés prenatal consumían más alcohol en la edad adulta. La depresión y el estrés se han asociado fuertemente con la dependencia al alcohol. Con un metaanálisis reciente en el que se incluyeron datos de 54 estudios en los que en conjunto se habían reclutado 40 749 personas, se confirmó que el polimorfismo 5-HTTLPR del promotor del gen que codifica para el transportador de serotonina modera la asociación entre el estrés y la depresión y el alelo corto (<

El consumo riesgoso y dañino de alcohol y sus factores predictivos en adolescentes estudiantes del bachillerato / Hazardous and harmful drinking among Mexican adolescents: prevalence and predictive factors

Alcohol is commonly used among adolescents in Mexico. In a representative survey of Mexico's general population, 30% of the teenagers reported current drinking, whereas 8% incurred in binge drinking (5 or more drinks per occasion) at least once during the last year. In addition, 3% reported three or more alcohol dependence symptoms over the last 12 months. In this Mexican age group, alcohol consumption importantly contributes to the most frequent causes of morbidity and mortality (e.g. accidents, violence, homicides, suicide and risky behaviors). Data from a representative survey of adolescents attending middle and high school in Mexico City suggests that adolescents attending Mexico's schools run a high risk for alcohol problems. In this study, prevalence of lifetime and current drinking, and of current binge drinking (5 or more drinks per occasion) were, respectively, 65.8%, 35.2%, and 23.8%. These rates are substantially higher than those described in teenagers from Mexico's general population. Furthermore, although among Mexico's general population the prevalence of drinking has traditionally been higher among male than female adolescents, no gender differences in prevalence of alcohol consumption have been reported among Mexican middle and high school students. This suggests that female adolescents in Mexico's schools have become equally exposed to drinking as their male counterparts. Despite these trends, there is a paucity of studies examining drinking patterns and their respective correlates among Mexican adolescents attending post-elementary education. To our knowledge, in this population, there are no published prevalence estimates of Hazardous and Harmful Drinking (HHD). HHD is defined as a pattern of alcohol consumption conferring to the individual a greater risk for health problems, or frankly conducive to medical or psychological complications (e.g. accidents, victimization, violence, alcohol dependence, liver cirrhosis and/or other medical complications). The Alcohol Use Disorders Identification Test (AUDIT), developed by the World Health Organization, is currently the only instrument specifically designed to identify HHD. Although the AUDIT was initially validated only among adult patients in primary care settings, this instrument has consistently shown to be valid and reliable in detecting alcohol problems in different populations, such as the adolescent population in many countries around the world. Given the public health implications of estimating the frequency of HHD among adolescents attending high school in Mexico, and given the importance of elucidating the variables influencing this problem, we decided to conduct the analysis presented here. To our knowledge, this is the first report published in the international literature on the prevalence of HHD among adolescents attending high school in a Latin American country. Objective In the study described here, derived from a Universidad Nacional Autónoma de México (UNAM) project entitled <>, we aimed at examining the frequency and risk factors for HHD among Mexican high school students. More specifically, our objectives were: 1. to determine the past-year prevalence of HHD among high school freshmen; and 2. to examine, in this population, the effects of demographic and family variables in the likelihood of HHD. Subjects and methods This study was a cross-sectional survey conducted at the beginning of the school year during the registration period between September 1st and September 30th, 2005. In 2005, a total of 34000 students were accepted to initiate college at the nine UNAM college campuses located in the Mexico City metropolitan area. Of these, 28784 students (87.4 %) (age=14.8 [±2.5] years; 51.0% women) consented in answering the survey and provided complete data. Consequently, 521 6 students (12.6%) were excluded from the analysis due to a lack of consent, incomplete data or their absence at the time of registration. We used the AUDIT to examine past-year prevalence of HHD. This self-report instrument includes 10 items that examine frequency and intensity of drinking (items 1-3), presence of alcohol dependence symptoms (items 4-6), and negative consequences of drinking (items 7-10), yielding a maximum possible score of 40 points. Among adult patients in primary care settings, it has been accepted that an AUDIT score of 0-7 points reflects safe levels of alcohol consumption, whereas a score of 8 points or higher indicates the presence of Hazardous and/or Harmful Drinking. It has been described however, that among adolescents, an AUDIT score of 3 points or higher reliably identifies those students experiencing this problem. In the analysis presented here, we separately examined and reported prevalence estimates and correlates for HHD using both AUDIT's cut-off scores (≥3 and ≥8). The AUDIT was administered at the same time that a wellness screening survey that the UNAM Medical Services routinely administer to all registering high school freshmen at the beginning of the school year. Questions in the wellness survey pertained students' medical and dental health, family medical history, immunizations, and use of tobacco and other drugs. In addition, demographic and socioeconomic information was obtained from a questionnaire also routinely administered by the UNAM registrar's office. This questionnaire included 37 items inquiring about gender, age, employment and marital status, monthly family income, parental education, place and type of residency, persons with whom the student resided, and questions on previous academic performance. We estimated the prevalence of HHD and their respective 95% confidence intervals (95% CI) in the total of the sample, and separately by age group, gender, working status, monthly family income, parental education, and by variables reflecting whether the students lived with their family, peers, or alone. These variables were modeled using simulated binary terms (0, 1). Subsequently, a multinomial logistic regression was used to examine the relationship between HHD and the demographic and socioeconomic variables listed above. Variables were entered simultaneously into the logistic regression equation. To summarize the level of risk of HHD conferred by significant variables in the logistic regression model, odds ratios (OR) and their respective 95% CI's were estimated. All the significant effects reported here were adjusted considering the effects of the remaining demographic and socioeconomic variables. Results Among the high school students examined here, the prevalence of HHD was 4.0% when an AUDIT cut-off score of ≥ 8 was used. When an AUDIT score of ≥3 was considered, a frequency of 1 7.2% was observed. Men (AUDIT ≥8: 5.4%; AUDIT ≥3: 21.4%) experienced this problem more frequently than women (AUDIT≥8: 2.6%; AUDIT≥3: 13.1%). The highest prevalence of HHD among men was observed in all age groups and regardless of working status, family income, parents' education, or regardless of the persons with whom the student reported to live with. Controlling for demographic and socioeconomic differences between men and women, we found that the risk of experiencing HHD among men was approximately two times higher than among women (OR's and 95% CI's for AUDIT's cut-off score ≥8 or ≥3, respectively 2.0[1.6-2.4] and 1.6[1.5-1.8]).

De acuerdo a la Encuesta Nacional de Adicciones (ENA) (Medina-Mora et al., 2003), de 1990 al 2002, la prevalencia en el consumo de alcohol durante los últimos 12 meses entre los jóvenes mexicanos de 12 a 17 años de edad, se elevó del 27.6% al 30%. De manera más reciente, la Encuesta de Estudiantes de Nivel Medio y Medio Superior de la Ciudad de México (EENMMS) (Villatoro et al., 2003), describió que el consumo alguna vez en la vida y el consumo durante el último mes de bebidas etílicas afectó respectivamente al 65.8% y al 35.2% de los estudiantes. Llama la atención que la frecuencia del consumo alguna vez en la vida reportada por la EENMMS es considerablemente mayor que la descrita en los adolescentes de la población general urbana (39.8%) por la ENA. Además, las diferencias de género reportadas por la ENA, en las que los hombres tradicionalmente beben con más frecuencia que las mujeres, no fueron encontradas por la EENMMS en la población estudiantil del nivel medio y medio superior. Hasta lo que nosotros sabemos, se desconoce cuál es la prevalencia en esta población de patrones de consumo problemático de alcohol como serían el consumo riesgoso y dañino (CRDA) o el consumo dependiente. Por lo que se desconoce si existen diferencias entre la población estudiantil y los adolescentes de la población general, en la prevalencia de estos problemas. El CRDA se define como un patrón de consumo de bebidas embriagantes, que se sitúa en un continuum de severidad, que coloca al sujeto en riesgo de desarrollar problemas de salud y/o que puede desembocar en francas complicaciones físicas y/o psicológicas (accidentes, victimización, violencia, dependencia al alcohol, etc.). Objetivo En el estudio que se presenta aquí, nos propusimos: 1) estimar la prevalencia durante el último año del CRDA en los estudiantes de primer ingreso al nivel bachillerato de la UNAM, y 2) evaluar la influencia de las variables sociodemográficas y familiares en el riesgo para el CRDA. Material y métodos El diseño del estudio fue el de una encuesta transversal en los estudiantes del primer año del bachillerato en el sistema escolarizado de la UNAM. Se estudiaron a 28 784 estudiantes (87.4 % de la población total). Se utilizó el Alcohol Use Disorders Identification Test (AUDIT) -versión en español para detectar el CRDA en la población adolescente. En este análisis empleamos tanto los puntos de corte recomendados para evaluar el CRDA en adultos (AUDIT≥8) como el puntaje recomendado para la población adolescente (AUDIT≥3). Se utilizaron porcentajes, promedios y desviaciones estándar para el análisis de las variables demográficas, y pruebas de contraste de medias (análisis de varianza) y de proporciones ( χ²) de acuerdo a la variable. Se utilizó la regresión logística multinomial para examinar la asociación de las variables demográficas y familiares con el CRDA. Se calcularon los odds ratios (OR) con intervalo de confianza al 95% para resumir el nivel de riesgo de ser afectado por el CRDA. Resultados Cuando se usó la definición del CRDA para la población adulta, se encontró que 4.0% de los estudiantes lo presentaron, frente a 1 7.2% cuando se utilizó el puntaje del AUDIT recomendado para los adolescentes. El riesgo de experimentar el CRDA fue casi dos veces mayor en los hombres que en las mujeres.

Prevalencia del consumo riesgoso y dañino de alcohol y factores de riesgo en estudiantes universitarios de primer ingreso / Prevalence of risky and harmful alcohol consumption and risk factors in freshmen students

Background In Mexico, alcohol is the most widely used substance among young adults. Alcohol consumption in this age group contributes importantly to the most frequent causes of mortality and morbidity (e.g., accidents, violence, homicides, suicide and risky behaviors). Around the world, college or university attendance has emerged in the literature as a risk factor for drinking problems among young adults. In Mexico, data from the most recent National Survey on Addictions showed that lifetime and current drinking is experienced by more than half of the Mexicans attending college education. Despite this, in our country there is a paucity of epidemiological studies examining drinking behavior and correlates among those attending college. Findings in non-representative samples of students attending public and private universities in Mexico City suggest that, during the last two decades, there has been an increase in the frequency of lifetime and current drinking in this population. Additionally, these studies have shown that, in comparison to young adults of the same age in the general population, university students may experience a greater prevalence of lifetime and current alcohol drinking. Regarding the frequency of unhealthy drinking among Mexican college students, to our knowledge there are no prevalence estimates of hazardous or harmful drinking published. However, observations in non-random samples of university students in Mexico City suggested that at least one in three men and one in five women incurred in unhealthy drinking (e.g., ≥ 5 drinks per occasion or drinking to intoxication) at least once during the last month. Hazardous and harmful drinking is respectively defined by a pattern of alcohol consumption conferring a greater risk for health problems or that is frankly conducive to medical or psychological complications (e.g., accidents, victimization, violence, alcohol dependence, liver cirrhosis and/or other medical complications). The Alcohol Use Disorders Identification Test (AUDIT), developed by the World Health Organization, is currently the only instrument specifically designed to identify hazardous and harmful drinking. Although the AUDIT was initially validated among older adult patients in primary care settings, this instrument has consistently shown to be valid and reliable in detecting alcohol problems in different populations such as the college students in many countries around the world. Given the public health implications of estimating the frequency of hazardous and harmful drinking among college students in Mexico, and given the importance of elucidating the variables influencing this problem, we decided to conduct the present study. To our knowledge, this is the first report published in the international literature on the prevalence of hazardous and harmful drinking among college students in a Latin American country. Objective In the analysis described here, derived from the project entitled Early Identification and Treatment of Problem Drinkers at the National Autonomous University of Mexico (UNAM), our aim was to examine the frequency and risk factors for hazardous and harmful drinking among Mexican university students. More specifically, our objectives were: 1. To determine the past-year prevalence of hazardous and harmful drinking among UNAM college freshmen; and 2. To examine in this population the effects of demographic and family variables on the likelihood of hazardous and harmful drinking. Subjects and methods This study was a cross-sectional survey that was conducted at the beginning of the school year during the registration period between September 1st and September 30th, 2005. In 2005, a total of 34 000 students were accepted to initiate college at the nine UNAM college campuses located in the Mexico City metropolitan area. Of these, 24 921 (73.3%) students (age=18.7±4.3 years; 55.7% women) consented in answering the survey and provided complete data. Consequently, 9 079 students (26.7%) were excluded from the analysis due to lack of consent, incomplete data or due to their absence at the time of registration. We used the Alcohol Use Disorders Identification Test (AUDIT) to examine past-year prevalence of hazardous and harmful drinking. This self-report instrument includes 10 items that examine frequency and intensity of drinking (items 1-3), presence of alcohol dependence symptoms (items 4-6) and negative consequences of drinking (items 7-10), yielding a maximum possible score of 40 points. Among adult patients in primary care settings, it has been accepted that an AUDIT score of 0-7 points reflects safe levels of alcohol consumption, whereas a score of 8 points or greater indicates the presence of hazardous and harmful drinking. It has been described, however, that among college students, an AUDIT score of 6 points or greater reliably identifies those students experiencing this problem. In the analysis presented here, we separately examined and reported the prevalence estimates and correlates of hazardous and harmful drinking using both AUDIT cut-off scores (≥ 6 and ≥ 8). The AUDIT was administered at the same time as a wellness screening survey that the UNAM Medical Services routinely administer to all registering freshmen at the beginning of the school year. Questions in the wellness survey pertained students' medical and dental health, family medical history, immunizations, use of tobacco and other drugs. In addition, demographic and socioeconomic information was obtained from a questionnaire also routinely administered by the UNAM registrar's office. This questionnaire included 37 items inquiring about gender, age, employment and marital status, monthly family income, parental education, place and type of residency, persons with whom the student resided, and questions on previous academic performance.

Antecedentes En México, el alcohol es la sustancia potencialmente adictiva que se utiliza con mayor frecuencia por los adultos jóvenes. Información proveniente de la Encuesta Nacional de Adicciones más reciente muestra que más de 50% de los jóvenes entre los 18-29 años ha consumido bebidas alcohólicas al menos una vez durante el último mes. En la Ciudad de México se ha encontrado que más de la mitad de las mujeres y cerca de dos terceras partes de los hombres entre 18-29 años de edad consume regularmente bebidas alcohólicas. Durante los últimos años, el consumo de bebidas alcohólicas se ha venido incrementando importantemente entre los jóvenes mexicanos de ambos sexos en edad de recibir una educación superior. A nivel internacional, la bibliografía sugiere que la población estudiantil de los centros de educación superior es un grupo de mayor riesgo para el desarrollo de problemas por consumo de alcohol. En México, aunque se desconoce si los estudiantes de educación superior son un grupo de mayor riesgo para estos abusos, algunas encuestas y reportes sugieren que los problemas por consumo de alcohol tienen una importancia creciente. En cuanto al consumo de alcohol que excede los niveles seguros para la salud (≥2 bebidas estándar al día en las mujeres o ≥3 bebidas estándar al día en los hombres), el Observatorio Mexicano del Alcohol y Drogas describió que en el año 2002 el consumo de cinco o más copas por ocasión de consumo afecta a tres de cinco hombres y a una de cinco mujeres. Aunque problemas metodológicos y sesgos de selección potenciales en estas encuestas dificultan su interpretación, sus resultados sugieren que el consumo de alcohol, particularmente el consumo riesgoso y potencialmente dañino, es común entre los estudiantes universitarios de la Ciudad de México. El consumo riesgoso y dañino de alcohol (CRDA) se sitúa en un continuum de severidad y se define como un patrón de consumo de bebidas embriagantes que colocan al sujeto en riesgo de desarrollar problemas de salud y/o que desemboca en francas complicaciones físicas y/o psicológicas (accidentes, victimización, violencia, dependencia al alcohol, cirrosis hepática, etc.). De acuerdo a los reportes de la bibliografía internacional, este es el primer estudio publicado sobre la prevalencia de consumo peligroso y dañino de alcohol en estudiantes universitarios en América Latina. Objetivo En el trabajo que se presenta aquí, que forma parte del proyecto para la Identificación Temprana y Tratamiento Oportuno de bebedores con Consumo Excesivo de Alcohol en Estudiantes Universitarios de la UNAM, nos propusimos evaluar la prevalencia del CRDA durante el último año y examinar los factores de riesgo y protección respectivos en estudiantes de primer ingreso a la licenciatura de la Universidad Nacional Autónoma de México. De manera especifica, nos propusimos: 1) estimar la prevalencia del CRDA durante el último año en los estudiantes de primer ingreso a la licenciatura de la UNAM, y 2) evaluar en esta población la influencia de las variables sociodemográficas y familiares en el riesgo para el CRDA. Material y métodos Se trató de un estudio transversal en el que se estudiaron 24921 estudiantes del primer año de la licenciatura de la UNAM (edad=18.7±4.3 años; 55% mujeres). Para detectar aquellos estudiantes que en el último año incurrieron en el CRDA, se utilizó el instrumento de tamizaje Alcohol Use Disorder Identification Test (AUDIT). Se utilizó la regresión logística multinomial para examinar los efectos de las variables demográficas y sociofamiliares, así como para calcular Odds Ratios (OR) y sus respectivos intervalos de confianza al 95%. Este instrumento consiste de 10 preguntas que exploran la frecuencia e intensidad del consumo de bebidas alcohólicas. Con el objetivo de poder comparar nuestros hallazgos con los de otros investigadores, se examinaron y se reportan separadamente las prevalencias del CRDA con base en puntos de corte de 8 y de 6 en el AUDIT. Para el reporte de datos demográficos y puntajes del AUDIT, se utilizaron porcentajes, promedios y desviaciones estándar. Se emplearon las pruebas de contraste de medias (análisis de varianza) y de proporciones (χ2) dependiendo de la naturaleza de cada variable. Se calcularon las prevalencias del CRDA con sus respectivos intervalos de confianza al 95%. Resultados Usando un puntaje de corte en el AUDIT de ocho y de seis puntos, la prevalencia del CRDA durante el último año fue respectivamente de 11.1% y de 18.4%. Esta fue mayor en los hombres (AUDIT≥8: 17.3%; AUDIT≥6: 27.4%) que en las mujeres (AUDIT≥8: 6.2%; AUDIT≥6: 11.3%). Además del sexo masculino, aquellos estudiantes que trabajaban y que reportaron un mayor ingreso familiar mensual, tuvieron un mayor riesgo de experimentar el CRDA. En las mujeres, pero no en los hombres, un mayor nivel educativo tanto en el padre como en la madre también se relacionó con un incremento en el CRDA. Contrariamente, una mayor edad y el ser casado se asoció con una reducción en el riesgo del CRDA.

La epigenética y los estudios en gemelos en el campo de la psiquiatría / Epigenetics and twin studies in psychiatric domains

The sequence of the human genome integrates the keystone of our life. Part of it is transcribed to RNA, which in turn provides the information required by our cells to produce proteins. Discoveries in the genetics field have been essential to medicine and have been used to develop strategies to modify, prevent and propose new therapeutic approaches for human diseases. In the 19th Century, Gregor Johann Mendel developed a theoretical model which was able to predict in an accurate way hereditary mechanisms; indeed, his laws still explain the basis of human inheritance. Almost ninety years later, James Watson and Francis Crick announced their double-helix model of the DNA molecule. Then, positional cloning and the polymerase chain reaction (PCR) were introduced; more recently, almost 99% of the sequence of our genome was made public. The current period of time is known as the post-genomic era, due to the fact that researchers are not only obtaining the complete sequences of thousands of genomes, but are also searching for clues that may help understand the mechanisms that affect gene activation and deactivation, in which epigenetic factors are also involved. In medical domains, twins constitute a suitable group to study inherited disorders. Dizygotic or fraternal twins are produced by different egg and sperm cells, and even when these two fertilization events occur simultaneously, dizygotic twins share approximately the same percentage of genetic material than any pair of siblings, that is, around 50%. Some authors have suggested that the tendency for spontaneous dizygotic twinning could be attributed to a double ovulation which is genetically determined in an autosomal dominant manner. Monozygotic, as opposed to dizygotic twins, are produced by a single zygote whose cells are dissociated and originate two independent organisms; approximately a third of monozygotic twins are separated before the 5th day after fertilization, and the rest between the 5th and the 15th day. Most monozygotic twins are very similar; nevertheless, some few exceptions prove that in fact they actually do not have to be identical. Relatives of a person with a mental disorder tend to share traits associated with this disease, especially if the patient and the relative are monozygotic twins. However, important differences may be detected even between each pair of identical twins. Parameters such as concordance and heritability have shown that a monozygotic twin can develop an inherited disorder while his or her co-twin will always be disease-free. In addition to differences in susceptibility to inherited diseases, this kind of twins can display dissimilarities in somatic cell mutations (more overtly noticeable when ageing), their set of antibodies and T cell receptors, their number of mitochondrial DNA molecules, and chromosome X inactivation patterns in women, all of which are the main subject of many ongoing studies. A recent report shows that from 160 monozygotic twin pairs who were 3 to 74 years old, epigenetic patterns were identical early in life, but differences were more obvious at older ages, especially if twins were raised apart or if they had different medical history. Medical conditions, but also environmental factors such as pregnancy tobacco exposure, physical activity, and diet could contribute to differences in epigenetic patterns. It has been shown that epigenetic modifications (or epi-mutations) are more frequent than the ones that modify DNA sequence, so they are part of the fundamental causes of biological diversity, and they show how environment can modulate gene expression and contribute to our phenotype. Even when twin studies are sometimes considered purely genetic, they also give information about the influence of environmental factors. However, it is important to consider with caution the results from this type of studies. Heritability estimates are not unchangeable facts. They depend on the sample being analyzed, the genes involved in the specific sample, the characteristics of the environmental factors which members of this group were exposed to, and the precise moment the study was done. Epigenetics refers to changes that do not alter the DNA sequence but affect gene function due to chemical modifications which mainly occur in DNA cytosines and in chromatin-related histones. Epigenetic processes are covalent modifications which include the addition of functional groups (methyl, acetyl, phosphate, etc.) or proteins (ubiquitin, SUMO, etc.) to the DNA molecule or to associated proteins. These modifications contribute to the activation or inhibition of transcription, which leads to changes in messenger ARN expression that can ultimately influence the onset of disease. Pseudogenes are still being excluded while new genes are being confirmed in our genome sequence, but the current estimates indicate that each one of our nucleated cells contains almost 22000 genes (excluding mitochondrial DNA) which encode for polypeptides and more than 4,000 whose final product is RNA. Gene expression is partially controlled by DNA coiling around globular proteins called histones, which constitute a structure known as chromatin, a DNA-protein complex that represents the packaging of 3.25 billion base pairs of our genetic information. Physical and chemical chromatin modifications can also affect gene expression by changing DNA-protein interactions; in general terms, genes are inhibited when chromatin is packed and they are active when it is free. These dynamic states are controlled by epigenetic reversible modifications on DNA methylation or by changes in histones. It has been shown that subtle epigenetic differences between any two human beings are associated with dissimilar final chromatin remodeling, as well as expression/repression of genes.

La secuencia de ADN genómico que caracteriza a nuestra especie constituye la piedra fundamental de la vida humana; parte de ella se refleja en la secuencia del ARN y a través de éste se dicta la información necesaria para que nuestras células produzcan proteínas. La genética contribuye de manera importante a los avances en el campo médico. Los descubrimientos genéticos han permitido desarrollar estrategias para modificar, prevenir y proponer nuevas terapias para diversas enfermedades. En el siglo XIX, Gregor Johann Mendel desarrolló un modelo teórico capaz de predecir la naturaleza y propiedades de los mecanismos de la herencia, que sigue siendo indispensable para explicar la base de la herencia humana. Otro suceso determinante en la historia de la Medicina se dio a conocer casi nueve décadas después cuando James Watson y Francis Crick describieron su modelo estructural para el ADN. Posteriormente se introdujeron la clonación posicional y la reacción en cadena de la polimerasa; más recientemente se publicó cerca del 99% de la secuencia del genoma humano. El período actual se conoce como la era post-genómica, ya que además de descifrar genomas completos, los investigadores pretenden, entre otras cosas, esclarecer los mecanismos que influyen en la activación e inactivación de los genes, lo cual en parte involucra un nivel epigenético. En las ciencias médicas los gemelos constituyen un grupo idóneo para abordar el estudio de las enfermedades hereditarias. En este tipo de padecimientos suelen observarse similitudes entre parientes, en especial si se trata de gemelos monocigóticos. Sin embargo, aun en este tipo de hermanos se detectan diferencias importantes. Parámetros como los grados de concordancia y porcentajes de heredabilidad han puesto de manifiesto que un gemelo monocigótico puede presentar trastornos hereditarios que su co-gemelo nunca tendrá. La epigenética es el estudio de los cambios en la función de los genes que no afectan la secuencia del ADN, por modificaciones que tienen lugar principalmente en las citosinas de éste y en las histonas de la cromatina. Se ha determinado que las modificaciones epigenéticas son mucho más frecuentes que aquellas que modifican la secuencia del ADN, por lo que constituyen uno de los fundamentos de la diversidad biológica, muestran la manera en que el ambiente puede modular la expresión genética y contribuyen así a nuestro fenotipo. Esta revisión reúne datos sobre la posible relevancia de la epigenética en el estudio de los trastornos mentales y como posible explicación parcial de las diferencias observadas entre gemelos <>. Un conocimiento más profundo de los patrones epigenéticos podría contribuir a identificar factores de riesgo para estos trastornos.

[Mental health in a municipality of the State of Querétaro: a community-based psychiatric research model]. / La salud mental en el municipio de Querétaro: un modelo de investigación psiquiátrica en la comunidad.

The main object of this study was to determine, by means of a house-to-house survey, prevalence of mental disorders and type of alcohol consumption in an underprivileged population from a municipality in the State of Querétaro, Mexico. Results show that there was an 18.26% prevalence of psychiatric disorders with psychiatric comorbility of 56.8%. Anxiety disorders with 14.9% were the most frequent diagnosis and additional problems in descending order were affective disorders (10.2%), alcohol abuse and dependency (4.9%), schizophrenia (2%), and drug abuse (1.2%). Total prevalence was above that reported previously in Mexican population. There was a 48.8% association between unemployment and presence of one or more psychiatric disorders. Nearly 50% of male population had a problem with or excessive consumption of alcohol. These results lead us to consider that this is a high-risk population and that efforts must be made to continue these assessments to better determine prevalence of mental disorders and problems associated with them as well as the optimal mechanisms for attention to therm.

El efecto del zolpidem en los pacientes con insomnio de corta evolución / Effect of zolpidem in patients with short-term insomnia

Las alteraciones del sueño se consideran como un problema de salud en un alto porcentaje de la población y el insomnio es una de las alteraciones del sueño a las cuales se enfrenta comúnmente el médico general, ya que su prevalencia en la comunidad es aproximadamente de 33 por ciento; además, el insomnio puede provocar fatiga diurna y relacionarse con somnolencia, an-siedad y problemas de concentración y memoria, que pueden inducir deterioro social, laboral o de otras áreas importantes de la actividad cotidiana de los individuos. El abordaje terapéutico inicial es motivar a estos pacientes a que tengan hábitos higiénicos de sueño, pero cuando esta terapia no es suficiente se utilizan fármacos hipnóticos, como las benzodiazepinas (BDZ), que desafortunadamente, pueden causar tolerancia o dependencia física. Recientemente, se sintetizaron otros compuestos, como el zolpidem (ZPM), un inductor del sueño que tiene un perfil neurofarmacológico particular. Este trabajo tiene el propósito de evaluar los efectos clínicos del ZPM, y compararlos con los de la BDZ flunitrazepam (FNZ) en un grupo de pacientes con insomnio. En un estudio multicéntrico incluyeron 100 pacientes ambulatorios, entre 18 y los 65 años de edad, con el diagnóstico clínico de insomnio psicofisiológico de corta evolución. La evaluación del tratamiento se hizo mediante Cuestionario de Evaluación del Sueño, de Leeds (CESL), el Cuestionario de Sueño, del Hospital St. Mary (CSHSM), la Escala de Impresión Clínica Global (EICG) y la evaluación del perfil de seguridad clínica de los medicamentos utilizados. Las variables obtenidas se analizaron con varianza (ANOVA) de dos direcciones, y se utilizó un nivel de significancia de p<0.05. Ninguna de las comparaciones entre los fármacos estudiados mostró diferencias estadísticamente significativas. En el CESL, los factores: facilidad para dormir, calidad de sueño, despertar después del sueño y conducta después de despertar se redujeron después del tratamiento respecto de los valores basales, tanto con el ZPM (diferencias de -135.42; -98.40; -48.48; -47.86), como con el FNZ (-123.04; -91.42; -69.94; -76.60). En el CSHSM se identificaron los factores: latencia al sueño (LS), duración total de sueño (DTS), calidad de sueño (CS) y sueño satisfactorio (SS), los cuales también se modificaron con el tratamiento farmacológico

Conceptualización semántica de los términos hombre y mujer por estudiantes del primer año de medicina, UNAM / Semantic conceptualization of the terms man and woman among first year medical students

El objetivo de esta investigación es comprender el concepto semántico de las palabras hombre y mujer según lo procesan estudiantes del primer año de la carrera de médico cirujano en la Facultad de Medicina, UNAM, antes de que inicien el tema de la Sexualidad Humana en la asignatura de Psicología Médica. Resultados. Se aplicó un cuestionario a 163 estudiantes de 8 grupos seleccionados aleatoriamente. Los alumnos tendieron a verse más a sí mismos como fuertes, inteligentes y trabajadores, y veían a las mujeres como hermosas, inteligentes y propensas al amor. Por otro lado, las alumnas se expresaban de sí mismas como inteligentes, con amor y tiernas, y al hombre como fuerza, inteligentes y caballeros. Conclusión. Este estudio sugiere que tanto hombres como mujeres siguen jugando los roles que tanto la evolución como la sociedad les ha inculcado, aunque se muestra cierta tendencia a dar a la mujer un lugar intelectual mayor que antes (fundamentalmente desde el punto de vista de ellas) y el hombre sigue teniendo que mostrar su fuerza como forma de manejarse en la sociedad moderna.

El reconocimiento de la expresión facial de las emociones / Facial expression of emotions and its recognition

En este estudio preliminar se analizó el reconocimiento de la expresión facial de las emociones en una población mexicana de 204 sujetos clasificados de 4 grupos: 60 estudiantes universitarios y 96 obreros, que fungieron como testigos, y 48 pacientes psiquiátricos diagnosticados con los criterios del DSM-IV, 24 con depresión y 24 con esquizofrenia. Se utilizó como instrumento un conjunto de 6 pares de fotos, hombre y mujer, de actores profesionales, que expresaban las 6 emociones básicas según Ekman (tristeza, sorpresa, alergía, disgusto, miedo e ira). La suma de los aciertos se comparó por medio de ANOVA simple y la proporción de aciertos para cada foto se comparó por medio de contrastes Xi². Se encontró que los pacientes esquizofrénicos mostraban una menor capacidad de reconocimiento, como se ha señalado en la bibliografía internacional. Se analizan los resultados de los casos testigo en relación con la utilización de los vocablos que califican emoción en el habla coloquial mexicana