The influence of FKBP5 genotype on expression of FKBP5 and other glucocorticoid-regulated genes, dependent on trauma exposure.

The FK506 binding protein 51 (FKBP5), an intrinsic regulator of the glucocorticoid receptor, has been associated with pathological behaviors particularly in the context of childhood trauma (CT), via a putatively regulatory polymorphism, rs1360780. However, trans- and cis-acting effects of this locus and its interaction with CT are incompletely understood. To study its effects on the expression of glucocorticoid-regulated genes including FKBP5, we used lymphoblastoid cell lines (LCLs) derived from 16 CT-exposed patients with greater than two substance dependence/suicidal behavior diagnoses (casesCT+) and 13 non-CT-exposed controls (controlsCT-). This study in LCLs measures long-term trait-like differences attributable to genotype or lasting epigenetic modification. Through analysis of differential allelic expression (DAE) using an FKBP5 3'-UTR reporter single nucleotide polymorphism (SNP), rs3800373, that is in strong linkage disequilibrium with rs1360780, we confirmed that the rs1360780 risk allele (A) (or conceivably that of a linked SNP) leads to higher FKBP5 expression in controlsCT-. Intriguingly, casesCT+ did not show DAE, perhaps because of a genotype-predicted difference in FKBP5 DNA methylation restricted to casesCT+. Furthermore, through correlation analyses on FKBP5 expression at baseline and after induction by dexamethasone, we observed that casesCT+ had lower induction of FKBP5 expression, indicating that overall they may have strong ultra-short negative-feedback. Only casesCT+ showed an effect of rs1360780 genotype on expression of FKBP5 and other glucocorticoid-regulated genes. Together, these results confirm that the rs1360780 locus alters FKBP5 expression and further that in trans-fashion this locus affects the expression of other glucocorticoid-regulated genes after a glucocorticoid challenge. The CT exposure appears to be essential for trans-effects of rs1360780 on glucocorticoid-regulated genes.

Predictors for self-directed aggression in Italian prisoners include externalizing behaviors, childhood trauma and the serotonin transporter gene polymorphism 5-HTTLPR.

Suicidal behavior and self-mutilation can be regarded as the expression of self-directed aggression and both are common in prison populations. We investigated the influence of externalizing behaviors, depressive symptoms, childhood trauma, 5-HTTLPR variants on self-directed aggression (N = 145) in a group of 702 male Italian prisoners. Participants were comprehensively evaluated, including for psychiatric disorders, impulsive traits, lifetime aggressive behavior [Brown-Goodwin Lifetime History of Aggression (BGHA)], hostility, violent behavior during incarceration, depressive symptomatology [Hamilton Depression Rating Scale (HDRS)], childhood trauma [Childhood Trauma Questionnaire (CTQ)]. Logistic regression analysis showed false discovery rate corrected independent main effects of externalizing behaviors: BGHA (P = 0.001), violent behavior in jail (P = 0.007), extraversion (P = 0.015); HDRS (P = 0.0004), Axis I disorders (P = 0.015), CTQ (P = 0.004) and 5-HTTLPR genotype (P = 0.02). Carriers of 5-HTTLPR high (LA LA ), intermediate (LA LG , SLA ) activity variants were more likely to have exhibited self-directed aggression relative to the low activity (LG LG , SLG , SS) variant: high/low: odds ratio (OR) = 2.3, 95% confidence interval (CI) 1.27-4.68, P = 0.007; intermediate/low: OR = 1.96, 95% CI 1.09-3.68, P = 0.025. The CTQ main effect was driven by physical abuse. There was no interactive effect of 5-HTTLPR and CTQ. Secondary logistic regression analyses in (1) all suicide attempters (N = 88) and (2) all self-mutilators (N = 104), compared with controls showed that in both groups, childhood trauma (P = 0.008-0.01), depression (P = 0.0004-0.001) were strong predictors. BGHA, violent behavior in jail predicted self-mutilation (P = 0.002) but not suicide attempts (P = 0.1). This study was able to distinguish differing influences on self-directed aggression between groups of closely related predictor variables within the externalizing behavioral domain. 5-HTTLPR had an independent, variant dosage effect.

Expression of glutamatergic genes in healthy humans across 16 brain regions; altered expression in the hippocampus after chronic exposure to alcohol or cocaine.

We analyzed global patterns of expression in genes related to glutamatergic neurotransmission (glutamatergic genes) in healthy human adult brain before determining the effects of chronic alcohol and cocaine exposure on gene expression in the hippocampus. RNA-Seq data from 'BrainSpan' was obtained across 16 brain regions from nine control adults. We also generated RNA-Seq data from postmortem hippocampus from eight alcoholics, eight cocaine addicts and eight controls. Expression analyses were undertaken of 28 genes encoding glutamate ionotropic (AMPA, kainate, NMDA) and metabotropic receptor subunits, together with glutamate transporters. The expression of each gene was fairly consistent across the brain with the exception of the cerebellum, the thalamic mediodorsal nucleus and the striatum. GRIN1, encoding the essential NMDA subunit, had the highest expression across all brain regions. Six factors accounted for 84% of the variance in global gene expression. GRIN2B (encoding GluN2B), was up-regulated in both alcoholics and cocaine addicts (FDR corrected P = 0.008). Alcoholics showed up-regulation of three genes relative to controls and cocaine addicts: GRIA4 (encoding GluA4), GRIK3 (GluR7) and GRM4 (mGluR4). Expression of both GRM3 (mGluR3) and GRIN2D (GluN2D) was up-regulated in alcoholics and down-regulated in cocaine addicts relative to controls. Glutamatergic genes are moderately to highly expressed throughout the brain. Six factors explain nearly all the variance in global gene expression. At least in the hippocampus, chronic alcohol use largely up-regulates glutamatergic genes. The NMDA GluN2B receptor subunit might be implicated in a common pathway to addiction, possibly in conjunction with the GABAB1 receptor subunit.

The interactive effect of MAOA-LPR genotype and childhood physical neglect on aggressive behaviors in Italian male prisoners.

Aggressive disorders are moderately heritable; therefore, identification of genetic influences is important. The X-linked MAOA gene, encoding the MAOA enzyme, has a functional 30 bp repeat polymorphism in the promoter region (MAOA-LPR) that has been shown to influence aggression. Childhood trauma is a known risk factor for numerous psychopathologies in adulthood including aggressive behaviors. We investigated the interactive effect of MAOA-LPR genotype and a history of childhood trauma in predicting aggressive behaviors in a prisoner population. A total of 692 male prisoners were genotyped for MAOA-LPR with genotypes grouped into high and low transcriptional activity. Participant evaluations included measures of aggression (Brown-Goodwin Lifetime History of Aggression, BGHA), hostility (Buss-Durkee Hostility Inventory), impulsivity (Barratt Impulsiveness Scale), violence directed toward self and others, and childhood trauma [Childhood Trauma Questionnaire (CTQ)]. MAOA-LPR interacted with CTQ physical neglect (PN), the most common (47%) form of childhood trauma in this sample, to predict BGHA aggression (P = 0.002). Within the group not exposed to PN, carriers of the MAOA-LPR high-activity variant were more aggressive: (tR = 2.47, P < 0.014). We observed a crossover effect in that the increase in aggression scores with PN was greater in low-activity individuals (tR = 5.55, P < 0.0001) than in high-activity individuals (tR = 4.18, P < 0.0001). These findings suggest that childhood trauma and the functional MAOA-LPR polymorphism may interact to specifically increase risk for over aggressive behavior but not impulsivity or hostility. The MAOA-LPR low-activity variant may be protective against the development of aggressive behavior under low stress conditions, at least in this prisoner population.

The CRHR1 gene, trauma exposure, and alcoholism risk: a test of G × E effects.

The corticotropin-releasing hormone type I receptor (CRHR1) gene has been implicated in the liability for neuropsychiatric disorders, particularly under conditions of stress. On the basis of the hypothesized effects of CRHR1 variation on stress reactivity, measures of adulthood traumatic stress exposure were analyzed for their interaction with CRHR1 haplotypes and single-nucleotide polymorphisms (SNPs) in predicting the risk for alcoholism. Phenotypic data on 2533 non-related Caucasian individuals (1167 alcoholics and 1366 controls) were culled from the publically available Study of Addiction: Genetics and Environment genome-wide association study. Genotypes were available for 19 tag SNPs. Logistic regression models examined the interaction between CRHR1 haplotypes/SNPs and adulthood traumatic stress exposure in predicting alcoholism risk. Two haplotype blocks spanned CRHR1. Haplotype analyses identified one haplotype in the proximal block 1 (P = 0.029) and two haplotypes in the distal block 2 (P = 0.026, 0.042) that showed nominally significant (corrected P < 0.025) genotype × traumatic stress interactive effects on the likelihood of developing alcoholism. The block 1 haplotype effect was driven by SNPs rs110402 (P = 0.019) and rs242924 (P = 0.019). In block 2, rs17689966 (P = 0.018) showed significant and rs173365 (P = 0.026) showed nominally significant, gene × environment (G × E) effects on alcoholism status. This study extends the literature on the interplay between CRHR1 variation and alcoholism, in the context of exposure to traumatic stress. These findings are consistent with the hypothesized role of the extra hypothalamic corticotropin-releasing factor system dysregulation in the initiation and maintenance of alcoholism. Molecular and experimental studies are needed to more fully understand the mechanisms of risk and protection conferred by genetic variation at the identified loci.

A preliminary study suggests that nicotine and prefrontal dopamine affect cortico-striatal areas in smokers with performance feedback.

Nicotine and tonic dopamine (DA) levels [as inferred by catechol-O-methyl tranferase (COMT) Val158Met genotype] interact to affect prefrontal processing. Prefrontal cortical areas are involved in response to performance feedback, which is impaired in smokers. We investigated whether there is a nicotine × COMT genotype interaction in brain circuitry during performance feedback of a reward task. We scanned 23 healthy smokers (10 Val/Val homozygotes, 13 Met allele carriers) during two fMRI sessions while subjects were wearing a nicotine or placebo patch. A significant nicotine × COMT genotype interaction for BOLD signal during performance feedback in cortico-striatal areas was seen. Activation in these areas during the nicotine patch condition was greater in Val/Val homozygotes and reduced in Met allele carriers. During negative performance feedback, the change in activation in error detection areas such as anterior cingulate cortex (ACC)/superior frontal gyrus on nicotine compared to placebo was greater in Val/Val homozygotes compared to Met allele carriers. With transdermal nicotine administration, Val/Val homozygotes showed greater activation with performance feedback in the dorsal striatum, area associated with habitual responding. In response to negative feedback, Val/Val homozygotes had greater activation in error detection areas, including the ACC, suggesting increased sensitivity to loss with nicotine exposure. Although these results are preliminary due to small sample size, they suggest a possible neurobiological mechanism underlying the clinical observation that Val/Val homozygotes, presumably with elevated COMT activity compared to Met allele carriers and therefore reduced prefrontal DA levels, have poorer outcomes with nicotine replacement therapy.

Functional genetic variants that increase synaptic serotonin and 5-HT3 receptor sensitivity predict alcohol and drug dependence.

The 5-HT3 receptor is rapidly potentiated by ethanol and mediates fast excitatory serotonin (5-HT) transmission that modulates dopamine release in the reward circuitry. The 5-HT transporter regulates synaptic 5-HT availability. Functional polymorphisms in genes encoding the transporter and receptor may therefore influence addiction vulnerability. In this study, 360 treatment-seeking African American male patients with single and comorbid DSM-IV lifetime diagnoses of alcohol, cocaine and heroin dependence and 187 African American male controls were genotyped for the triallelic 5-HTTLPR functional polymorphism in the 5-HT transporter gene (SLC6A4) and 16 haplotype-tagging single-nucleotide polymorphisms (SNPs) across HTR3B (including the functional rs1176744 Tyr129Ser) and HTR3A, genes encoding 5-HT3 receptors. The HTR3B rs1176744 gain-of-function Ser129 allele predicted alcohol dependence (P=0.002) and low 5-HTTLPR activity predicted cocaine/heroin dependence (P=0.01). Both the HTR3B Ser129 allele (P=0.014, odds ratio (OR)=1.7 (1.1-2.6)) and low 5-HTTLPR activity (P=0.011, OR=2.5 (1.3-4.6)) were more common in men with alcohol+drug dependence compared with controls. Moreover, the HTR3B Ser129 allele and low 5-HTTLPR activity had an additive (but not an interactive) effect on alcohol+drug dependence (OR=6.0 (2.1-16.6)) that accounted for 13% of the variance. One possible explanation of our findings is that increased synaptic 5-HT coupled with increased 5-HT3 receptor responsiveness may result in enhanced dopamine transmission in the reward pathway, a predictor of increased risk for addiction. Our results may have pharmacogenetic implications for 5-HT3 therapeutic antagonists such as ondansetron.

Early life stress, MAOA, and gene-environment interactions predict behavioral disinhibition in children.

Several, but not all, studies have shown that the monoamine oxidase A functional promoter polymorphism (MAOA-LPR) interacts with childhood adversity to predict adolescent and adult antisocial behavior. However, it is not known whether MAOA-LPR interacts with early life (pre-birth-3 years) stressors to influence behavior in prepubertal children. The Avon Longitudinal Study of Parents and Children, UK, is a community-representative cohort study of children followed from pre-birth onwards. The impact of family adversity from pre-birth to age 3 years and stressful life events from 6 months to 7 years on behavioral disinhibition was determined in 7500 girls and boys. Behavioral disinhibition measures were: mother-reported hyperactivity and conduct disturbances (Strengths and Difficulties Questionnaire) at ages 4 and 7 years. In both sexes, exposure to family adversity and stressful life events in the first 3 years of life predicted behavioral disinhibition at age 4, persisting until age 7. In girls, MAOA-LPR interacted with stressful life events experienced from 6 months to 3.5 years to influence hyperactivity at ages 4 and 7. In boys, the interaction of MAOA-LPR with stressful life events between 1.5 and 2.5 years predicted hyperactivity at age 7 years. The low activity MAOA-LPR variant was associated with increased hyperactivity in girls and boys exposed to high stress. In contrast, there was no MAOA-LPR interaction with family adversity. In a general population sample of prepubertal children, exposure to common stressors from pre-birth to 3 years predicted behavioral disinhibition, and MAOA-LPR- stressful life event interactions specifically predicted hyperactivity.

COMT Val158Met and cognition: main effects and interaction with educational attainment.

Studies in children have shown that the genetic influence on cognition is positively correlated with socioeconomic status. Catechol-O-methyltransferase (COMT) Val158Met, a common, functional polymorphism, has been implicated in executive cognition and working memory. Imaging studies have shown that the variant Met allele is associated with more efficient prefrontal cortical processing and better attention but also emotional vulnerability to stress. We hypothesized that COMT Val158Met genotype would interact with years of education (yrs ed), one indicator of socioeconomic adversity, to predict cognitive task performance. We therefore administered the Wechsler Adult Intelligence Scale-Revised (WAIS-R) to 328 community-derived, genotyped, Plains American Indians (mean yrs ed = 12; range = 5-18). We found significant genotypic effects on WAIS-R measures of long-term memory, working memory and attention. The Met allele was associated with improved performance in the Information and Picture Completion subscales; Met/Met homozygotes performed the best. COMT genotype interacted with yrs ed to influence Information and Block Design scores: Met allele carriers' scores improved markedly with increasing yrs ed, whereas the scores of Val/Val individuals were only marginally influenced by yrs ed. There was a crossover of effects at 11-12 yrs ed: in the less educated group, Met allele carriers actually performed worse than Val/Val individuals perhaps because of emotional vulnerability to educational adversity, but in the better educated group, Met allele carriers excelled. Our study in Plains American Indians has shown that COMT Val158Met influences several aspects of cognition and some of its effects are moderated by educational adversity.

Interaction between a functional MAOA locus and childhood sexual abuse predicts alcoholism and antisocial personality disorder in adult women.

Women who have experienced childhood sexual abuse (CSA) have an increased risk of alcoholism and antisocial personality disorder (ASPD). Among male subjects, a functional polymorphism (MAOA-LPR, monoamine oxidase A linked polymorphic region) in the promoter region of the monoamine oxidase A gene (MAOA) appears to moderate the effect of childhood maltreatment on antisocial behavior. Our aim was to test whether MAOA-LPR influences the impact of CSA on alcoholism and ASPD in a sample of 291 women, 50% of whom have experienced CSA; we also tested whether haplotypes covering the region where both MAOA and monoamine oxidase B (MAOB) genes are located predict risk of alcoholism and ASPD better than the MAOA-LPR locus alone. Participants included 168 alcoholics (39 with ASPD (antisocial alcoholics) and 123 controls (no alcoholics, no ASPD). Antisocial behavior was also modeled as a continuous trait: ASPD symptoms count. The MAOA-LPR low activity allele was associated with alcoholism (P=0.005), particularly antisocial alcoholism (P=0.00009), only among sexually abused subjects. Sexually abused women who were homozygous for the low activity allele had higher rates of alcoholism and ASPD, and more ASPD symptoms, than abused women homozygous for the high activity allele. Heterozygous women displayed an intermediate risk pattern. In contrast, there was no relationship between alcoholism/antisocial behavior and MAOA-LPR genotype among non-abused women. The MAOA-LPR low activity allele was found on three different haplotypes. The most abundant MAOA haplotype containing the MAOA-LPR low activity allele was found in excess among alcoholics (P=0.008) and antisocial alcoholics (P=0.001). Finally, a MAOB haplotype, which we termed haplotype C, was significantly associated with alcoholism (P=0.006), and to a lesser extent with antisocial alcoholism (P=0.03). In conclusions, MAOA seems to moderate the impact of childhood trauma on adult psychopathology in female subjects in the same way as previously shown among male subjects. The MAOA-LPR low activity allele appears to confer increased vulnerability to the adverse psychosocial consequences of CSA. Haplotype-based analysis of the MAOA gene appeared to strengthen the association, as compared to the MAOA-LPR locus alone. A MAOB haplotype was associated with alcoholism independently from ASPD.

Alcoholism is associated with GALR3 but not two other galanin receptor genes.

The neuropeptide galanin is widely expressed in the periphery and the central nervous system and mediates diverse physiological processes and behaviors including alcohol abuse, depression and anxiety. Four genes encoding galanin and its receptors have been identified (GAL, GALR1, GALR2 and GALR3). Recently we found that GAL haplotypes were associated with alcoholism, raising the possibility that genetic variation in GALR1, GALR2 and GALR3 might also alter alcoholism risk. Tag single nucleotide polymorphisms (SNPs) were identified by genotyping SNP panels in controls from five populations. For the association study with alcoholism, six GALR1, four GALR2 and four GALR3 SNPs were genotyped in a large cohort of Finnish alcoholics and non-alcoholics. GALR3 showed a significant association with alcoholism that was driven by one SNP (rs3,091,367). Moreover, the combination of the GALR3 rs3,091,367 risk allele and GAL risk haplotypes led to a modestly increased odds ratio (OR) for alcoholism (2.4) as compared with the effect of either GAL (1.9) or GALR3 alone (1.4). Likewise, the combination of the GALR3 and GAL risk diplotypes led to an increased OR for alcoholism (4.6) as compared with the effect of either GAL (2.0) or GALR3 alone (1.6). There was no effect of GALR1 or GALR2 on alcoholism risk. This evidence suggests that GALR3 mediates the alcoholism-related actions of galanin.

Association of galanin haplotypes with alcoholism and anxiety in two ethnically distinct populations.

The neuropeptide galanin (GAL) is widely expressed in the central nervous system. Animal studies have implicated GAL in alcohol abuse and anxiety: chronic ethanol intake increases hypothalamic GAL mRNA; high levels of stress increase GAL release in the central amygdala. The coding sequence of the galanin gene, GAL, is highly conserved and a functional polymorphism has not yet been found. The aim of our study was, for the first time, to identify GAL haplotypes and investigate associations with alcoholism and anxiety. Seven single-nucleotide polymorphisms (SNPs) spanning GAL were genotyped in 65 controls from five populations: US and Finnish Caucasians, African Americans, Plains and Southwestern Indians. A single haplotype block with little evidence of historical recombination was observed for each population. Four tag SNPs were then genotyped in DSM-III-R lifetime alcoholics and nonalcoholics from two population isolates: 514 Finnish Caucasian men and 331 Plains Indian men and women. Tridimensional Personality Questionnaire harm avoidance (HA) scores, a dimensional measure of anxiety, were obtained. There was a haplotype association with alcoholism in both the Finnish (P=0.001) and Plains Indian (P=0.004) men. The SNPs were also significantly associated. Alcoholics were divided into high and low HA groups (>or= and

Neurocognitive impairment due to chronic alcohol consumption in an American Indian community.

OBJECTIVE: Studies have shown that clinically ascertained alcoholics tend to have lower scores than nonalcoholics on cognitive performance tests, particularly the Block Design (BD) and Digit Symbol (DS) tests of the Weschler Adult Intelligence Scale-Revised (WAIS-R). The aim of this study was to determine whether similar differences are found in a community sample of Plains Indian men and women with an episodic pattern of drinking and a high lifetime prevalence of alcoholism (71% for men, 44% for women). METHOD: We administered a truncated form of the WAIS-R to 334 members of a Plains Indian tribe (197 women and 137 men). Blind-rated psychiatric diagnoses were assigned according to Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III-R) criteria and based on the Schedule for Affective Disorders, Lifetime Version (SADS-L) interview. We compared 68 currently drinking alcoholics (38 men and 30 women), 116 abstaining alcoholics (59 men and 57 women) and 150 nonalcoholics (40 men and 110 women). RESULTS: Current and past heavy drinking had no impact on WAIS-R scores in women. Male alcoholics who were abstinent > or = 2years had similar scores to nonalcoholic men. Male current drinkers showed a trend for lower overall verbal and performance (PIQ) scores and BD performance subtest. Further analysis showed that drinking for > or = 15 years was significantly associated with reduced DS in male current drinkers. CONCLUSIONS: These findings suggest that for the men in this community sample, the impact on PIQ is due to the direct effect of chronic alcohol consumption on cognitive performance and is at least partially reversible after 2 years of abstinence.

EEG phenotype in alcoholism: increased coherence in the depressive subtype.

OBJECTIVE: Electroencephalography (EEG) power and coherence changes may be trait markers for alcoholism providing clues to brain mechanisms of vulnerability. However, it is unclear whether alpha power and coherence differences reflect reversible toxic or withdrawal effects of alcohol. METHOD: The EEGs of 10 non-abstinent and 16 long-term abstinent alcoholics (7.7 +/- 5.8 years) and 25 controls were analyzed. Levels of anxiety and depression were assessed by questionnaire. RESULTS: No statistically significant EEG power differences were observed between groups, although the numerical difference between alcoholics and controls was similar to that previously reported. Bilateral, intrahemispheric, posterior coherences were significantly increased in the alpha and beta frequency bands both in long-term abstinent and non-abstinent alcohol-dependent subjects - particularly when depressiveness was included as a covariate. CONCLUSION: These results suggest that increased EEG-coherence (cortical synchronization) may serve as endophenotype for alcoholism in conjunction with increased depressiveness and point to a possible involvement of GABAergic and/or glutamatergic neurotransmission.

Alcohol use disorders and anxiety disorders: relation to the P300 event-related potential.

BACKGROUND: The robust association of alcoholism with reduced P300 event-related potential amplitude has been largely established in severely affected alcoholics and their offspring. Few studies have examined the relationship of increased arousal, anxiety, and P300. In this study, we sought to determine whether P300 group differences could be discerned in well functioning individuals with less severe forms of alcohol use disorders and anxiety disorders. We were particularly interested in looking at the subgroup of alcohol use disorders accompanied by anxiety disorders. This subgroup has previously been found to have diminished alpha amplitude in the resting EEG. METHODS: Male and female community volunteers (99 unrelated index participants and 78 relatives) and 21 unrelated volunteers from an anxiety disorder clinic were interviewed by using the Schedule for Affective Disorders and Schizophrenia, Lifetime version. Blind-rated lifetime psychiatric diagnoses were assigned according to DSM-III-R criteria. Auditory and visual P300 event-related potentials were elicited with an oddball paradigm and were recorded at the midparietal (Pz) site. RESULTS: As expected, auditory P300 amplitudes were significantly reduced in participants with alcohol use disorders and significantly increased in participants with lifetime anxiety disorders. However, more detailed analysis revealed that, in an apparent paradox, auditory P300 amplitudes were lowest in individuals with comorbid alcohol use and anxiety disorders and highest in individuals with anxiety disorders alone. Visual P300 amplitudes followed the same trends but were generally not significant. CONCLUSIONS: Even in a sample of largely community-ascertained individuals, auditory P300 amplitude is reduced in alcoholics, particularly those with anxiety disorders, and is highest in nonalcoholics with anxiety disorders.

Does a reduced sensitivity to bitter taste increase the risk of becoming nicotine addicted?

Cigarette smoking appears to be on the increase in adolescents. The initiation of regular smoking nearly always begins before adulthood. It is therefore crucial to find ways of identifying those children most vulnerable to nicotine addiction and prioritizing them for preventive measures. We hypothesized that individuals who, in a simple taste test, perceive phenylthiocarbamide (PTC) as bitter may find the taste of cigarettes aversively bitter and could therefore have a reduced vulnerability to nicotine addiction compared to nontasters, who would be the group at greater risk of addiction. We studied 242 Plains American Indians, 136 women and 106 men aged 18-59 years, and found that (allowing for gender differences and the possible direct effects of smoking on taste) the proportion of PTC nontasters to tasters in smokers, even light smokers, was significantly greater than in both nonsmokers and social smokers (chi2= 15.875, 4 df; P=.003), suggesting that nontasters, who are not aversive to the bitter taste of cigarettes, may be more at risk for heavy smoking and therefore more vulnerable to nicotine addiction.

The genetics of alcoholism and alcohol abuse.

Twin studies have established that there are substantial genetic influences on alcoholism (0.5-0.6) in both men and women. Our knowledge of behaviors predisposing to alcoholism, including anxiety and impulsivity, is advancing rapidly through animal and human studies. Although alcoholism is often comorbid with other substance abuse and psychiatric disorders, recent studies have shown that, with the exception of nicotine, the heritability of alcoholism is largely substance-specific. Increasing understanding of the neurobiology of addiction has identified neural pathways in which genetic variation at candidate genes could influence vulnerability. Some functional variants of these genes have been identified. Recent linkage analyses in humans and rodents have pointed to genomic regions harboring genes that influence alcoholism. Refinement of clinical phenotypes and use of intermediate phenotypes will improve chances of gene identification. All these advances in the understanding of the genetics of alcoholism should facilitate the development of more accurately targeted therapies using molecular diagnostic approaches.

Sexually dimorphic relationship of a 5-HT2A promoter polymorphism with obsessive-compulsive disorder.

BACKGROUND: In an earlier analysis of 73 subjects from this study, the reduced activity catechol O-methyltransferase variant was shown to be associated with obsessive-compulsive disorder in men only. We hypothesized that the 5-HT2A promoter polymorphism, -1438G>A, previously associated with anorexia nervosa, would be more abundant in women with obsessive-compulsive disorder. METHODS: One hundred and one Caucasian obsessive-compulsive disorder patients (48 women, 53 men) and 138 control subjects (77 women, 61 men), were genotyped. DSM-III-R psychiatric diagnoses were assigned based on the SCID-I. RESULTS: As hypothesized, the -1438A allele frequency was higher in obsessive-compulsive disorder women (.57) than female control subjects (.42) (p =.015). The genotype frequencies were also significantly different (p =.020). Allele frequencies did not differ between male obsessive-compulsive disorder patients (.44) and male control subjects (.41). CCONSLUSIONS: We have found that a 5-HT2A promoter polymorphism is associated with obsessive-compulsive disorder in women but not in men, strengthening the argument that there may be fundamental gender differences in the genetic susceptibility to obsessive-compulsive disorder.