Relation between age of first drinking and mental health and alcohol and drug disorders in adulthood: evidence from a 35-year cohort study

Aims To estimate associations between age of first drinking (AFD) and alcohol use disorder, nicotine dependence, cannabis dependence, illicit drug dependence, major depression and anxiety disorder in adulthood, net of a series of covariate factors. Design Data were obtained from a longitudinal birth cohort. Setting Christchurch, New Zealand. Participants The Christchurch Health Development Study (CHDS), a longitudinal study of a cohort born in 1977 and studied to age 35 years. Analysis samples ranged in size from 1056 (ages 11–13 years) to 962 (age 35 years); 50.2% of the total sample was male. Measurements A measure of AFD (ages 5–13+ years) was generated using latent class analysis. Outcome measures included: major depression, anxiety disorders, alcohol use disorder, nicotine dependence, cannabis dependence and other illicit drug dependence during the period 15–35 years. Covariate factors measured during childhood included family socio‐economic status, family functioning, parental alcohol‐related attitudes/behaviours and individual factors. Findings Earlier AFD was associated significantly (P