Complex cannabis use patterns: Associations with cannabis consequences and cannabis use disorder symptomatology.

BACKGROUND: Historically, cannabis researchers have assumed a single mode and product of cannabis (e.g., smoking plant). However, patterns of use, products (e.g., concentrates, edibles), and modes (e.g. blunts, vaporizers) are diversifying. This study sought to: 1) classify cannabis users into groups based on their use of the full range of cannabis products, and 2) examine user group differences on demographics, cannabis consequences and cannabis use disorder (CUD) symptomatology. METHODS: In a sample of college students (data collected in Fall 2017), who used cannabis in the past year (N = 1390), latent class analysis (LCA) was used to characterize cannabis users. We then added demographic characteristics, cannabis consequences, and CUD symptomatology scores separately to LCA models to examine class differences. RESULTS: Five unique classes emerged: high-frequency all-product users, high-frequency plant/moderate-frequency edible and concentrate users, low-frequency plant users, moderate-frequency plant and edible users, and low-frequency edible users. Demographic characteristics, cannabis consequences, and CUD symptomatology differed across classes characterized by frequency as well as product. CONCLUSIONS: Results reflect the increasing variety of cannabis products, modes, and use patterns among college students. In this sample, frequency of use remains a strong predictor of cannabis-related consequences, in addition to type of product. As variation in cannabis use patterns continue to evolve, it is essential for researchers to conduct comprehensive assessments.

Concordance between the diagnostic guidelines for alcohol and cannabis use disorders in the draft ICD-11 and other classification systems: analysis of data from the WHO's World Mental Health Surveys.

BACKGROUND AND AIMS: The World Health Organization's (WHO's) proposed International Classification of Diseases, 11th edition (ICD-11) includes several major revisions to substance use disorder (SUD) diagnoses. It is essential to ensure the consistency of within-subject diagnostic findings throughout countries, languages and cultures. To date, agreement analyses between different SUD diagnostic systems have largely been based in high-income countries and clinical samples rather than general population samples. We aimed to evaluate the prevalence of, and concordance between diagnoses using the ICD-11, The WHO's ICD 10th edition (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders, 4th and 5th editions (DSM-IV, DSM-5); the prevalence of disaggregated ICD-10 and ICD-11 symptoms; and variation in clinical features across diagnostic groups. DESIGN: Cross-sectional household surveys. SETTING: Representative surveys of the general population in 10 countries (Argentina, Australia, Brazil, Colombia, Iraq, Northern Ireland, Poland, Portugal, Romania and Spain) of the World Mental Health Survey Initiative. PARTICIPANTS: Questions about SUDs were asked of 12 182 regular alcohol users and 1788 cannabis users. MEASUREMENTS: Each survey used the World Mental Health Survey Initiative version of the WHO Composite International Diagnostic Interview version 3.0 (WMH-CIDI). FINDINGS: Among regular alcohol users, prevalence (95% confidence interval) of life-time ICD-11 alcohol harmful use and dependence were 21.6% (20.5-22.6%) and 7.0% (6.4-7.7%), respectively. Among cannabis users, 9.3% (7.4-11.1%) met criteria for ICD-11 harmful use and 3.2% (2.3-4.0%) for dependence. For both substances, all comparisons of ICD-11 with ICD-10 and DSM-IV showed excellent concordance (all κ ≥ 0.9). Concordance between ICD-11 and DSM-5 ranged from good (for SUD and comparisons of dependence and severe SUD) to poor (for comparisons of harmful use and mild SUD). Very low endorsement rates were observed for new ICD-11 feature for harmful use ('harm to others'). Minimal variation in clinical features was observed across diagnostic systems. CONCLUSIONS: The World Health Organization's proposed International Classification of Diseases, 11th edition (ICD-11) classifications for substance use disorder diagnoses are highly consistent with the ICD 10th edition and the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV). Concordance between ICD-11 and the DSM 5th edition (DSM-5) varies, due largely to low levels of agreement for the ICD harmful use and DSM-5 mild use disorder. Diagnostic validity of self-reported 'harm to others' is questionable.

Concordance of ICD-11 and DSM-5 definitions of alcohol and cannabis use disorders: a population survey.

The proposed criteria for alcohol and cannabis use disorders in the 11th edition of ICD (ICD-11) will be presented to the World Health Assembly in 2017, but the beta-phase descriptions have been released. We compared them with those in the tenth edition (ICD-10) and the American Psychiatric Association's DSM fourth edition (DSM-IV) and fifth edition (DSM-5), in a nationally representative sample of adult Australians. Disorders were assessed with the WHO World Mental Health Composite International Diagnostic Interview. The proportions classified as being dependent on alcohol and cannabis were similar with ICD-10, ICD-11, and DSM-IV, whereas for DSM-5, the proportion of lifetime users meeting the criteria for moderate to severe use (most comparable to dependence in the other systems) was far higher. We assessed whether criteria for alcohol and cannabis use described unidimensional syndromes for each, and all definitions seemed to do so. Classification of alcohol and cannabis use disorders, although simplified in ICD-11, was in almost perfect agreement with the classifications of ICD-10 and DSM-IV. With DSM-5, use disorder seemed to capture a different aspect of problematic use and selected a different group of individuals from the other systems. How the newest definitions will become used remains to be seen. The choice of classification might depend on the clinical population of interest.

Marijuana use from adolescence to adulthood: developmental trajectories and their outcomes.

BACKGROUND: The study assesses the degree to which individuals in different trajectories of marijuana use are similar or different in terms of unconventional behavior, sensation seeking, emotional dysregulation, nicotine dependence, alcohol dependence/abuse, children living at home, and spouse/partner marijuana use at age 43. METHOD: This study used a longitudinal design. The sample participants (N = 548) were first studied at mean age 14 and last studied at mean age 43. RESULTS: Six trajectories of marijuana use were identified: chronic/heavy users (3.6 %), increasing users (5.1 %), chronic/occasional users (20 %), decreasers (14.3 %), quitters (22.5 %), and nonusers/experimenters (34.5 %). With three exceptions, as compared with being a nonuser/experimenter, a higher probability of belonging to the chronic/heavy, the increasing, or the chronic/occasional user trajectory group was significantly associated with a greater likelihood of unconventional behavior, sensation seeking, emotional dysregulation, nicotine dependence, alcohol dependence/abuse, not having children who lived at home, and having a spouse/partner who used marijuana at early midlife. In addition, compared with being a quitter, a higher probability of belonging to the chronic/heavy user trajectory group was significantly associated with a higher likelihood of unconventional behavior, sensation seeking, emotional dysregulation, alcohol dependence/abuse, and spouse/partner marijuana use. Implications for intervention are presented. CONCLUSIONS: Trajectories of marijuana use, especially chronic/heavy use, increasing use, and chronic/occasional use, are associated with unconventional behavior, sensation seeking, emotional dysregulation, nicotine dependence, alcohol dependence/abuse, having children who lived at home, and spouse/partner marijuana use at age 43. The importance of the findings for prevention and treatment programs are discussed.

Genome-wide Association Study of Cannabis Dependence Severity, Novel Risk Variants, and Shared Genetic Risks.

IMPORTANCE: Cannabis dependence (CAD) is a serious problem worldwide and is of growing importance in the United States because cannabis is increasingly available legally. Although genetic factors contribute substantially to CAD risk, at present no well-established specific genetic risk factors for CAD have been elucidated. OBJECTIVE: To report findings for DSM-IV CAD criteria from association analyses performed in large cohorts of African American and European American participants from 3 studies of substance use disorder genetics. DESIGN, SETTING, AND PARTICIPANTS: This genome-wide association study for DSM-IV CAD criterion count was performed in 3 independent substance dependence cohorts (the Yale-Penn Study, Study of Addiction: Genetics and Environment [SAGE], and International Consortium on the Genetics of Heroin Dependence [ICGHD]). A referral sample and volunteers recruited in the community and from substance abuse treatment centers included 6000 African American and 8754 European American participants, including some from small families. Participants from the Yale-Penn Study were recruited from 2000 to 2013. Data were collected for the SAGE trial from 1990 to 2007 and for the ICGHD from 2004 to 2009. Data were analyzed from January 2, 2013, to November 9, 2015. MAIN OUTCOMES AND MEASURES: Criterion count for DSM-IV CAD. RESULTS: Among the 14 754 participants, 7879 were male, 6875 were female, and the mean (SD) age was 39.2 (10.2) years. Three independent regions with genome-wide significant single-nucleotide polymorphism associations were identified, considering the largest possible sample. These included rs143244591 (ß = 0.54, P = 4.32 × 10-10 for the meta-analysis) in novel antisense transcript RP11-206M11.7;rs146091982 (ß = 0.54, P = 1.33 × 10-9 for the meta-analysis) in the solute carrier family 35 member G1 gene (SLC35G1); and rs77378271 (ß = 0.29, P = 2.13 × 10-8 for the meta-analysis) in the CUB and Sushi multiple domains 1 gene (CSMD1). Also noted was evidence of genome-level pleiotropy between CAD and major depressive disorder and for an association with single-nucleotide polymorphisms in genes associated with schizophrenia risk. Several of the genes identified have functions related to neuronal calcium homeostasis or central nervous system development. CONCLUSIONS AND RELEVANCE: These results are the first, to our knowledge, to identify specific CAD risk alleles and potential genetic factors contributing to the comorbidity of CAD with major depression and schizophrenia.

Examining the profile of high-potency cannabis and its association with severity of cannabis dependence.

BACKGROUND: Cannabis use is decreasing in England and Wales, while demand for cannabis treatment in addiction services continues to rise. This could be partly due to an increased availability of high-potency cannabis. METHOD: Adults residing in the UK were questioned about their drug use, including three types of cannabis (high potency: skunk; low potency: other grass, resin). Cannabis types were profiled and examined for possible associations between frequency of use and (i) cannabis dependence, (ii) cannabis-related concerns. RESULTS: Frequent use of high-potency cannabis predicted a greater severity of dependence [days of skunk use per month: b = 0.254, 95% confidence interval (CI) 0.161-0.357, p < 0.001] and this effect became stronger as age decreased (b = -0.006, 95% CI -0.010 to -0.002, p = 0.004). By contrast, use of low-potency cannabis was not associated with dependence (days of other grass use per month: b = 0.020, 95% CI -0.029 to 0.070, p = 0.436; days of resin use per month: b = 0.025, 95% CI -0.019 to 0.067, p = 0.245). Frequency of cannabis use (all types) did not predict severity of cannabis-related concerns. High-potency cannabis was clearly distinct from low-potency varieties by its marked effects on memory and paranoia. It also produced the best high, was preferred, and most available. CONCLUSIONS: High-potency cannabis use is associated with an increased severity of dependence, especially in young people. Its profile is strongly defined by negative effects (memory, paranoia), but also positive characteristics (best high, preferred type), which may be important when considering clinical or public health interventions focusing on cannabis potency.

Identifying classes of conjoint alcohol and marijuana use in entering freshmen.

The current study identified classes of conjoint marijuana and alcohol use in entering college freshmen using latent profile analysis (N = 772; 53% male, 60% White; Mage = 18). Results yielded 4 distinct groups: Class 1 (moderate drinking with recent marijuana use: 22% of sample), Class 2 (moderate drinking with no recent marijuana use: 25%), Class 3 (light drinking with no recent marijuana use: 40%) and Class 4 (heavy drinking with recent marijuana use: 14%). Separate pairwise contrasts examined cross-class differences in demographics and drinking behaviors, comparing differences in drinking when current marijuana use was controlled (Class 1 vs. 4) and differences in marijuana use when drinking was held relatively constant (Class 1 vs. 2). Among moderate drinkers, recent marijuana users were more likely to drink more than intended, drink to get drunk, and had more problems (including higher rates of blackouts, physical injury, and DUI) relative to peers who refrained from marijuana. No cross-class differences were found for alcohol expectancies or behavioral motives. Findings from these analyses show the presence of distinct groups of conjoint users with different drinking behaviors and consequence profiles, and suggest that conjoint alcohol-marijuana use may be more problematic overall than single substance involvement and highlight the need for developing campus prevention and intervention programs that address the increased risk from polysubstance involvement.

Typology of individuals with substance dependence based on a Montreal longitudinal catchment area study.

This study sought to develop a typology of individuals with substance dependence (ISD) based on a longitudinal survey (n = 2,434) and 121 ISD. The latter were divided into three groups: newly abstinent individuals, chronic dependents and acute dependents. Individuals' typology was developed by cluster analysis. Newly abstinent individuals had fewer emotional problems and mental disorders in the previous 12 months. Four classes of ISD were identified, labelled respectively "chronic multi-substance consumption and mental disorders comorbidities," "multi-substance consumption," "alcohol and marijuana consumption" and "alcohol consumption only." Strategies adapted to each of these profiles could be promoted for more effective treatment.

Consumo de alcohol, sustancias ilegales y violencia hacia la pareja en una muestra de maltratadores en tratamiento psicológico / Alcohol consumption, illicit substances, and intimate partner violence in a sample of batterers in psychological treatment

Este estudio tiene como objetivo analizar las características de consumo de alcohol y sustancias ilegales en una muestra de 572 maltratadores en tratamiento por orden judicial. Los resultados indican que la prevalencia de consumo de alcohol en el último año fue de 89,3%, mientras que dentro de las sustancias ilegales las prevalencias más altas fueron para cannabis (27,8%) seguido de cocaína (20,3%). Con el objetivo de analizar el posible efecto del consumo sobre los niveles de perpetración y victimización de agresiones hacia la pareja, se dividió la muestra en 4 grupos: no consumidores (16,3%), consumidores de alcohol (58,6%), consumidores de drogas ilegales (3,5%) y consumidores de alcohol y drogas ilegales (21,7%), encontrándose que el grupo de los no consumidores y el de los consumidores de alcohol son los que presentan los niveles más bajos en perpetración de agresiones psicológicas, físicas y sexuales y victimización de agresiones psicológicas y físicas, mientras que el grupo de consumidores de alcohol e ilegales es el que presenta los niveles más elevados. Los resultados hallados ponen de manifiesto la necesidad de evaluar el consumo de sustancias a la hora de diseñar protocolos de intervención con maltratadores

The purpose of this study is to analyze the alcohol and illicit substance consumption characteristics in a sample of 572 batterers in treatment by court order. The results indicate that the prevalence of alcohol consumption in the past year was 89.3%, whereas within illicit substances, the prevalences were higher for cannabis (27.8%), followed by cocaine (20.3%). In order to analyze the possible effect of consumption on levels of perpetration and victimization of partneraggression, the sample was divided into 4 groups: nonconsumers (16.3%), alcohol consumers (58.6%), illicit drug consumers (3.5%), and consumers of alcohol and illicit drugs (21.7%), finding that the groups of nonconsumers and alcohol consumers presented the lowest level of perpetration of psychological, physical, and sexual aggression and of victimization of psychological and physical aggression, whereas the group of consumers of alcohol and illicit drugs presented the highest levels. The results reveal the need to assess substance consumption when designing intervention protocols with batterers

Developmental trajectories of marijuana use from adolescence to adulthood: relationship with using weapons including guns.

This is the first study to assess the associations between the trajectories of marijuana use and other predictors of violent behavior with the use of guns or other weapons as well as stealing without the use of weapons among inner-city African Americans and Puerto Ricans (N = 838). Logistic regression analyses examined whether the longitudinal trajectories of marijuana use compared with the trajectory of no/low marijuana use predicted violent behavior. A higher Bayesian posterior probability (BPP) for the increasing marijuana use trajectory group (AOR = 3.37, P < .001), the moderate use of marijuana trajectory group (AOR = 1.98, P < .01), and the quitter trajectory group (AOR = 1.70, P < .05) was associated with an increased likelihood of engaging in violence (i.e., shooting or hitting someone with a weapon) compared with the BPP of the no use of marijuana trajectory group. Our results address a number of important public health and clinical issues. Public health funds might be spent on prevention programs focused on decreasing the use of marijuana, increasing educational retention, and decreasing contact with deviant associates. Understanding the psychosocial conditions related to the use of weapons is critical for individuals involved in the criminal justice system, physicians, and other health care providers in managing individuals who engage in violent behavior.

An evaluation of the proposed DSM-5 cannabis use disorder criteria using Australian national survey data.

OBJECTIVE: The aim of the current study was to evaluate the proposed cannabis use disorder criteria for the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) using epidemiological data. METHOD: Data came from the 2007 Australian National Survey of Mental Health and Wellbeing. Lifetime DSM-IV and DSM-5 cannabis use disorder diagnoses were assessed using a modified version of the World Mental Health Composite International Diagnostic Interview among those respondents who had used cannabis more than five times (n = 1,639; 37% female). RESULTS: The prevalence of cannabis use disorder decreased from DSM-IV (6.2%) to DSM-5 (5.4%). Two fifths of those with DSM-IV cannabis abuse would fall below the threshold for DSM-5 cannabis use disorder. More than a third of those classified as DSM-IV "diagnostic orphans" would meet criteria for a DSM-5 mild, moderate, or severe cannabis use disorder. In terms of demographic and clinical characteristics, those who converted from no disorder in DSM-IV to a disorder under DSM-5 were similar to those diagnosed with a disorder according to both systems. Those who converted to no disorder under DSM-5 tended to be young men with cross-substance involvement and high levels of cannabis consumption. CONCLUSIONS: Although a previous study of the Australian population found that alcohol use disorders increase considerably under DSM-5, the current study found a reduction in cannabis use disorders in the transition from DSM-IV to DSM-5. This is likely the result of the high ratio of cannabis abuse to dependence when compared with other substances. Given the implications the proposed changes have on the epidemiology of substance use disorders, further research is needed to determine whether the proposed criteria are optimal.

An assessment of the compatibility of DSM-IV and proposed DSM-5 criteria in the diagnosis of cannabis use disorders.

The current study used an automated version of the substance use disorder diagnostic schedule-IV (SUDDS-IV) to assess DSM-IV (fourth edition of the Diagnostic and statistical manual of mental disorders) and two sets of proposed DSM-5 (fifth edition of the Diagnostic and statistical manual of mental disorders) cannabis use disorder criteria among adult prison inmates in the Minnesota Department of Corrections state prison system from 2000 to 2003. Initially proposed DSM-5 criteria had only two diagnostic designations (moderate and severe). A subsequent revision added a mild designation and required a greater number of positive findings for the severe diagnosis. The sample was composed of 7,672 (89.6% male) inmates. Inmates with no DSM-IV diagnoses and most who currently received a cannabis dependence diagnosis according to the DSM-IV guidelines will fit into corresponding DSM-5 categories (i.e., no diagnosis and severe cannabis use disorder, respectively). Some diagnostic criteria, in addition to those proposed for the DSM-5, emerged as cardinal indicators of moderate cannabis use disorder. The study's limitations are noted.

Cannabis use stages as predictors of subsequent initiation with other illicit drugs among French adolescents: use of a multi-state model.

The aim of this study was to confirm the influence of cannabis use patterns on the probability of initiation with other illicit drugs (OID). A French nationwide retrospective cohort on drug use was reconstituted on 29,393 teenagers. A Markov multi-state model was fitted, modelling all possible pathways from initial abstinence to cannabis initiation, daily cannabis use and OID initiation. The model was adjusted for tobacco and alcohol use. The risk for OID initiation appeared 21 times higher among cannabis experimenters and 124 times higher among daily cannabis users than among non-users. Tobacco and alcohol use were associated with a greater risk of moving on to cannabis initiation (hazard ratio (HR)=1.2 for tobacco initiation, HR=2.6 for daily tobacco use and HR=2.8 for drunkenness initiation). The results of this study provide a confirmation of a stage process in drug use, mediated by cannabis and liable to lead to OID experiment. This is compatible with the literature on the gateway theory, but goes further by modelling the entire sequence of use. OID experiment could be a consequence of initial opportunity to use the more accessible illicit drug, cannabis.

The classification of Spanish adolescents based on substance consumption patterns and the analysis of the relationships within their social developmental contexts.

This research is part of the 2006 edition of the Health Behavior in School-aged Children (HBSC) study. The data presented were composed of a sample of 15942 Spanish adolescents ranging from 13 to 18 years of age. The instruments used included a variety of questions related to substance consumption among adolescents, their bio-psycho-social adjustment and developmental contexts, all of which are part of the HBSC study instrument bank. Through classification analysis, as well as significance and effect size tests, we obtained relevant information about the current epidemiology of substance consumption among Spanish adolescents. These results are representative of the Spanish adolescent population which allows the typical risk profile attributed to young people to be clarified. A gradual adjustment can be seen in terms of substance consumption levels in youth and that same level in their friends. Likewise, the analysis of the developmental context (family, friends and school) provides important information when it comes to preventing substance consumption, thus showing the advantages that coherence and connection have between the different environments where youth live, grow up and develop.

Cannabis with high cannabidiol content is associated with fewer psychotic experiences.

OBJECTIVE: Cannabis is associated with psychotic outcomes in numerous studies, an effect that is commonly attributed to Δ (9)-tetrahydrocannabinol (Δ 9-THC). An increasing number of authors identify cannabidiol, another component of the cannabis plant, as an antipsychotic agent. The objective of the current study is to investigate the role of cannabidiol content in the association between cannabis use and psychiatric symptoms in a large non-clinical population of cannabis users. METHODS: In a web-based cross-sectional study we obtained detailed information about cannabis use and subclinical psychiatric experiences using the Community Assessment of Psychic Experiences (CAPE). Different types of cannabis (i.e. marijuana, hashish etc.) have distinctive proportions of Δ 9-THC and cannabidiol. Since average concentrations of Δ 9-THC and cannabidiol in the most popular types of cannabis sold on the Dutch market are annually measured, we were able to estimate exposure to Δ 9-THC and cannabidiol. RESULTS: We included 1877 subjects (mean age 23, SD 6.0) who used the same type of cannabis in the majority of the occasions (in >60% of occasions). We found a significant inverse relationship (F(1,1877): 14.577, p<0.001) between cannabidiol content and self-reported positive symptoms, but not with negative symptoms or depression. The estimated effect size of cannabidiol content was small. CONCLUSION: Although the observed effects are subtle, using high cannabidiol content cannabis was associated with significantly lower degrees of psychotic symptoms providing further support for the antipsychotic potential of cannabidiol.

The 'grass ceiling': limitations in the literature hinder our understanding of cannabis use and its consequences.

AIM: To illustrate how limitations in the cannabis literature undermine our ability to understand cannabis-related harms and problems experienced by users and identify users at increased risk of experiencing adverse outcomes of use. METHOD AND RESULTS: Limitations have been organized into three overarching themes. The first relates to the classification systems employed by researchers to categorize cannabis users, their cannabis use and the assumptions on which these systems are based. The second theme encompasses methodological and reporting issues, including differences between studies, inadequate statistical control of potential confounders, the under-reporting of effect sizes and the lack of consideration of clinical significance. The final theme covers differing approaches to studying cannabis use, including recruitment methods. Limitations related to the nature of the data collected by researchers are discussed throughout, with a focus on how they affect our understanding of cannabis use and users. CONCLUSIONS: These limitations must be addressed to facilitate the development of effective and appropriately targeted evidence-based public health campaigns, treatment programmes and preventative, early intervention and harm minimization strategies, and to inform cannabis-related policy and legislation.

The validity of DSM-IV cannabis abuse and dependence criteria in adolescents and the value of additional cannabis use indicators.

AIMS: This study assessed the validity of DSM-IV cannabis abuse and dependence criteria in an adolescent general population sample and evaluated the usefulness of additional cannabis use indicators. DESIGN AND SETTING: Data came from the 2008 Survey on Health and Consumption during the Day of Defense Preparation (ESCAPAD), a cross-sectional self-administered survey conducted in France. PARTICIPANTS: The analytical sample comprised 3641 adolescents aged 17-19 years who reported cannabis use in the past 12 months. MEASUREMENTS: To assess DSM-IV criteria of cannabis abuse and dependence, the Munich Composite International Diagnostic Interview (M-CIDI) was used. As additional cannabis use indicators, daily use, use when alone and use before midday were assessed. Confirmatory factor analyses and two-parameter logistic item response theory (IRT) models were run. Differential item functioning was assessed using the IRT log-likelihood ratio approach. RESULTS: A one-factor model comprising both abuse and dependence criteria showed the best fit to the data. Abuse item legal problems showed the greatest severity, whereas dependence items larger/longer and tolerance were found least severe. Discriminatory power was lowest for impaired control and legal problems. Additional cannabis use indicators increased the precision of the overall DSM-IV criterion set. Gender-based differential item functioning was observed for items tolerance, withdrawal and use before midday. CONCLUSION: The current DSM conceptualization with two distinct and graded diagnostic classes has limited validity among adolescents. In forthcoming revisions of the classification system, several existing criteria should be revised or dropped, new indicators of substance use disorders should be included and gender should be considered.

Theoretical and observed subtypes of DSM-IV alcohol- and cannabis-use disorders in the Australian population.

OBJECTIVE: Using a polythetic combinatorial approach to diagnosing substance-use disorders according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), criteria inevitably leads to substantial clinical heterogeneity in the manifestation of these disorders. Not all theoretically possible combinations of symptoms are found in reports from North American samples. Cross-cultural differences in substance use and dependence make it important to consider patterns of problematic use in other countries. METHOD: The heterogeneity of DSM-IV alcohol- and cannabis-use disorders in Australia was explored by calculating the number of theoretically possible subtypes for these disorders based on the DSM-IV diagnostic criteria and identifying which of these subtypes are observed in the 1997 National Survey on Mental Health and Wellbeing. RESULTS: Of the theoretically possible subtypes, 55.6% were observed for alcohol dependence, 73.3% for alcohol abuse, 61.9% for cannabis dependence, and 53.3% for cannabis abuse. Four subtypes, containing only one criterion each, accounted for 87.5% of individuals with alcohol abuse. Fourteen subtypes characterized 70% of participants with alcohol dependence. One subtype, use in physically hazardous situations, accounted for 75.7% of individuals with cannabis abuse. Eight subtypes represented 72.3% of individuals with cannabis dependence. CONCLUSIONS: Alcohol and cannabis abuse appear to be homogeneous disorders, whereas alcohol and cannabis dependence are heterogeneous disorders, in Australia. All of the DSM-IV diagnostic criteria for substance dependence contributed to understanding the symptoms associated with these disorders among Australians. The importance of not making major decisions regarding the type and number of diagnostic criteria for a given disorder based on analysis of data from a single country was highlighted.

Marijuana use subtypes in a community sample of young adult women.

OBJECTIVE: This study sought to empirically derive marijuana user subtypes based on DSM abuse and dependence criteria and examine demographic and substance abuse distinctions of derived classes. METHOD: A community sample of 308 female marijuana users between the ages of 18 and 24 were recruited in the Southern New England region. Latent class analysis was used to derive subgroups based on DSM criteria. The use and demographic characteristics of classes were further analyzed using analysis of variance and the chi-square test. RESULTS: Based on fit criteria, a three-class solution was selected. Class I (37%)-an "unaffected/mild" group-was characterized by very low endorsement rates of abuse and dependence criteria. This class was also found to have significantly lower rates of other substance use problems. Class II (41.6%)-"moderate problem users"-showed moderate endorsement rates of abuse and dependence criteria. Class III (21.4%)-"severe problem users"-showed the greatest levels of abuse and dependence, with 90% meeting DSM criteria for abuse and 100% meeting diagnostic criteria for marijuana dependence. Class III also showed the greatest levels of other substance use problems. CONCLUSION: Three distinct marijuana abuse and dependence subtypes were derived using latent class analysis. Findings may have implications for the development of more targeted treatment and prevention interventions for young women struggling with varying degrees of marijuana abuse and dependence.

Typologies of cannabis users and associated characteristics relevant for public health: a latent class analysis of data from a nationally representative Canadian adult survey.

Cannabis is the most prevalently used illicit drug in Canada. Current policy consists primarily of universal use prohibition rather than interventions targeting specific risks and harms relevant for public health. This study aimed to identify distinct groups of cannabis users based on defined use characteristics in the Canadian population, and examine the emerging groups' associations with differential risk and harm outcomes. One thousand three hundred and three current (i.e. use in the past three months) cannabis users, based on data from the representative cross-sectional 2004 Canadian Addiction Survey (N = 13,909), were statistically assessed by a 'latent class analysis' (LCA). Emerging classes were examined for differential associations with socio-demographic, health and behavioral indicators on the basis of chi-square and analysis of variance techniques. Four distinct classes based on use patterns were identified. The class featuring earliest onset and highest frequency of use [22% of cannabis user sample or 2.2% (95% confidence interval (CI) = 1.8-2.7%) of the Canadian adult population] was disproportionately linked to key harms, including other illicit drug use, health problems, cannabis use and driving, and cannabis use problems. A public health framework for cannabis use is needed in Canada, meaningfully targeting effective interventions towards the minority of users experiencing elevated levels of risks and harms.