Background While several studies have shown a high association between cannabis use and use of other illicit drugs, the predictors of progression from cannabis to other illicit drugs remain largely unknown. This study aims to estimate the cumulative probability of progression to illicit drug use among individuals with lifetime history of cannabis use, and to identify predictors of progression from cannabis use to other illicit drugs use. Methods Analyses were conducted on the sub-sample of participants in Wave 1of the National Epidemiological Survey on Alcohol and Related Conditions (NESARC) who started cannabis use before using any other drug (n= 6,624). Estimated projections of the cumulative probability of progression from cannabis use to use of any other illegal drug use in the general population were obtained by the standard actuarial method. Univariate and multivariable survival analyses with time-varying covariates were implemented to identify predictors of progression to any drug use. Results Lifetime cumulative probability estimates indicated that 44.7% of individuals with lifetime cannabis use progressed to other illicit drug use at some time in their lives. Several sociodemographic characteristics, internalizing and externalizing psychiatric disorders and indicators of substance use severity predicted progression from cannabis use to other illicit drugs use. Conclusion A large proportion of individuals who use cannabis go on to use other illegal drugs. The increased risk of progression from cannabis use to other illicit drugs use among individuals with mental disorders underscores the importance of considering the benefits and adverse effects of changes in cannabis regulations and of developing prevention and treatment strategies directed at curtailing cannabis use in these populations.

Objective To construct a virtual space of common adolescent psychiatric disorders, spanned by factors reflecting major psychopathological dimensions, and locate psychiatric disorders in that space; examine whether the major psychopathological dimensions can be hierarchically organized; and determine the distribution of the latent scores of individuals in the space spanned by those dimensions. Method Exploratory factor analyses of data from the National Comorbidity Survey Adolescent Supplement (NCS-A) using the psychiatric diagnoses as indicators were used to identify the latent major psychopathological dimensions. The loadings of the disorders on those dimensions were used as coordinates to calculate the distance among disorders. The distribution of individuals in the space was based on the latent scores on the factors reflecting the major psychopathological conditions. Results A model with three correlated factors provided an excellent fit (Comparative Fit Index [CFI]=0.97, Tucker-Lewis Index [TLI]=0.95, the root mean squared error of approximation [RMSEA]=0.008) for the structure of disorders and a 4-factor model could be hierarchically organized, ultimately yielding a general psychopathology factor. Distances between disorders ranged from 0.079 (between social phobia and generalized anxiety disorder [GAD]) and 1.173 (between specific phobia and conduct disorder [CD]). At the individual level, there were 546 distinct liabilities observed (22% of all 2,455 potential liabilities). Conclusion A novel way of understanding psychiatric disorders in adolescents is as existing in a space with a limited number of dimensions with no disorder aligning along one single dimension. These dimensions are hierarchically organized, allowing for analyses at different levels of organization. Furthermore, individuals with psychiatric disorders present with a broad range of liabilities, reflecting the diversity of their clinical presentations.

Aims To develop a comprehensive etiological model of pathological gambling (PG) for men and women based on Kendler's development model for major depression, which groups 22 risk factors in 5 developmental tiers (childhood, early adolescence, late adolescence, adulthood, last year). We hypothesized that: 1) All risk factors would be significantly associated with PG; 2) The effect of risk factors in earlier developmental tiers would be accounted for by later tiers; and, 3) There would be few gender differences. Design Separate models were built for lifetime gambling and for 12-month PG among those with lifetime gambling. Setting Data drawn from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) in the USA. Participants Respondents to NESARC Wave 1 (n= 43093). Measurements Odds ratios (OR) and Adjusted OR (AOR) were used to determine the risk factors in multiple models. Findings After mutually adjusting for other risk factors, family history of substance use disorders (SUD) or depression, impulsivity, childhood-onset anxiety, number of Axis I and II disorders, history of SUD, nicotine dependence, social deviance in adulthood, and past-year history of SUD, nicotine dependence, and independent stressful life events predicted lifetime gambling. Past history of PG, number of personality disorders and past year nicotine dependence were significantly associated with 12-month PG (all p<.05). There were no significant gender interactions for 12-month PG. Conclusions A modification of Kendler's model for major depression provides a foundation for the development a comprehensive developmental model of pathological gambling. Lifetime history of gambling and 12-month pathological gambling appear to be determined by risk factors in several developmental levels, with the effect of earlier development tiers accounted for by later ones.