Objectives: The purpose of the present study was to examine the longitudinal association between early childhood factors and early initiation of use of substances and substance use disorders in a large prospective study.
Method: Data were from the Mater Hospital University of Queensland Study of Pregnancy, a prospective birth cohort study in Brisbane, Australia. Use of nicotine, alcohol and cannabis and age of initiation of such use were reported at the 21 year follow up. DSM-IV diagnosis of nicotine, alcohol and cannabis use disorders was assessed at 21 years using a computerized version of the Composite International Diagnostic Interview (CIDI-Auto). Early childhood factors were measured between mother's pregnancy and child age 5 years.
Results: Of the 3647 respondents with complete data, 15.4% had started to smoke cigarettes before 15 years. Another 17.4% and 12.2% reported having started to consume alcohol or use cannabis in early adolescence, respectively. Some 16.2%, 27.8% and 21.9% had ever had nicotine, alcohol or cannabis abuse or dependence (disorder) by 21 years, respectively. In multivariate models early initiation of use of substances, and substance use disorders were associated with disrupted families or drug-using parents, childhood problem behaviours, and poor parental monitoring and supervision in childhood.
Conclusions: There are four independent factors in early or middle childhood that predict early initiation of use of substances and subsequent substance use disorders by early adulthood. There is a need to consider whether what is known about the risk factors that predict young age of substance use, and substance use disorders, may be incorporated into treatment and/or prevention initiatives.