Cumulative and recent psychiatric symptoms as predictors of substance use onset: does timing matter?

Aims: We examined two questions about the relationship between conduct disorder (CD), depression and anxiety symptoms and substance use onset: (i) what is the relative influence of recent and more chronic psychiatric symptoms on alcohol and marijuana use initiation and (ii) are there sensitive developmental periods when psychiatric symptoms have a stronger influence on substance use initiation?

Design: Secondary analysis of longitudinal data from the Pittsburgh Youth Study, a cohort study of boys followed annually from 7 to 19 years of age.

Setting: Recruitment occurred in public schools in Pittsburgh, Pennsylvania, USA.

Participants: A total of 503 boys.

Measurements: The primary outcomes were age of alcohol and marijuana use onset. Discrete-time hazard models were used to determine whether (i) recent (prior year); and (ii) cumulative (from age 7 until 2 years prior to substance use onset) psychiatric symptoms were associated with substance use onset.

Findings: Recent anxiety symptoms [hazard ratio (HR) = 1.10, 95% confidence interval (CI) = 1.03-1.17], recent (HR = 1.59, 95% CI = 1.35-1.87), cumulative (HR = 1.45, 95% CI = 1.03-2.03) CD symptoms, and cumulative depression symptoms (HR = 1.04, 95% CI = 1.01-1.08) were associated with earlier alcohol use onset. Recent (HR = 1.39, 95% CI = 1.22-1.58) and cumulative CD symptoms (HR = 1.38, 95% CI = 1.02-1.85) were associated with marijuana use onset. Recent anxiety symptoms were only associated with alcohol use onset among black participants.

Conclusions: Timing matters in the relationship between psychiatric symptoms and substance use onset in childhood and adolescence, and the psychiatric predictors of onset are substance-specific. There is no single sensitive developmental period for the influence of psychiatric symptoms on alcohol and marijuana use initiation.