Childhood Externalizing Disorders Strongly Predict Problematic Cannabis Use Patterns in Adolescence

Five trajectories identified: stable-no problems (85%), early-onset high (2%), late-onset high (3%), early-onset low (6%), late-onset low (5%). Externalizing disorders at age 10 predicted three of four problem trajectories. Internalizing disorders were only associated with late-onset low problems (protective: RR=0.50). Short-term memory at age 8 was associated with late-onset high problems (RR=1.09).

Analysis within ALSPAC UK birth cohort. 6,049 participants with cannabis problem data (CAST) at 2+ timepoints between ages 15-24. Risk factors: internalizing and externalizing disorders at age 10, cognitive function at age 8. Longitudinal latent class analysis.

This study identifies a modifiable target for preventing problematic cannabis use: childhood externalizing disorders (conduct problems, ADHD-type behavior). Intervening on these behaviors at age 10 could potentially prevent cannabis problems starting at age 15.

The finding that externalizing but not internalizing disorders predict cannabis problems is clinically important. It suggests prevention efforts should focus on children with behavioral problems rather than anxious/depressed children, who may actually be at lower risk for some problem patterns.

59% female sample may affect generalizability. ALSPAC cohort is predominantly white (95.7%). Cannabis problems assessed by screening tool, not clinical diagnosis. Attrition from birth cohort may bias results.