The aims of the present study were to use population-level Australian data to estimate prevalence and speed of transitions across stages of alcohol and cannabis use, abuse and dependence, and remission from disorder, and consider the potential impacts that an individual’s age and sex cohort’s level of substance use predicted transitions into and out of substance use.
Data on lifetime history of use, DSM-IV use disorders, and remission from these disorders were collected from participants (n=8,463) in the 2007 Australian National Survey of Mental Health and Wellbeing using the Composite International Diagnostic Interview.
Lifetime prevalence of alcohol use, regular use, abuse, dependence, and remission from abuse and dependence were 94.1%, 64.5%, 22.1%, 4.0%, 16.1% and 2.1%, respectively. Unconditional lifetime prevalence of cannabis use, abuse, dependence, and remission from abuse and dependence were 19.8%, 6.1%, 1.9%, 4.0% and 1.5%. Increases in the estimated proportion of people in the respondent’s sex and age cohort who used alcohol/cannabis as of a given age were significantly associated with most transitions from use through to remission beginning at the same age.
Clear associations were documented between cohort-level prevalence of substance use and personal risk of subsequent transitions of individuals in the cohort from use to greater substance involvement. This relationship remained significant over and above associations involving the individual’s age of initiation. These findings have important implications for our understanding of the causal pathways into and out of problematic substance use.