Externalising pathways to alcohol-related problems in emerging adulthood.

Background: Both 'early-onset persistent' and 'adolescent-onset' conduct problems (CPs) are associated with alcohol-related problems in emerging adulthood. The escalation of early CPs into criminal behaviour and heavy alcohol consumption prior to emerging adulthood are both likely to be important pathways.

Methods: Data were analysed from 3,038 young people in a UK birth cohort, the Avon Longitudinal Study of Parents and Children. The exposure was developmental trajectories of CPs ('low', 'childhood-limited', 'adolescent-onset' and 'early-onset persistent') between ages 4 and 13 years. The mediator was latent classes representing heavy alcohol consumption and/ or criminal behaviour at age 15 years. For the outcome, a quadratic latent growth curve was estimated to capture nonlinear change in alcohol-related problems between ages 18 and 23 years.

Results: Those with 'early-onset persistent' [b(95% CI) = 1.16 (0.17, 2.14)] and 'adolescent-onset' CPs [b(95% CI) = 1.31 (0.17, 2.45)] had higher levels of alcohol-related problems at age 18 years compared to those with 'low' CPs', but there was little evidence of an association with alcohol-related problems after age 19 years. There was evidence for an indirect effect of 'early-onset persistent' CPs [b(95% CI) = 1.12 (0.52, 1.72)] on alcohol-related problems at age 18 years via the latent classes of alcohol and criminal behaviour in adolescence. This was not found for 'adolescent-onset' CPs [b(95% CI) = 0.35 (-0.36, 1.07)].

Conclusions: Strong associations exist between early CPs, adolescent alcohol consumption and criminal behaviour and alcohol-related problems at age 18 years. Associations between early CPs and alcohol-related problems weakened considerably across emerging adulthood.