Cannabis use and adult ADHD symptoms.
BACKGROUND
The present study examined the associations between cannabis use in adolescence and young adulthood and self-reported adult attention deficit/hyperactivity disorder (ADHD) symptoms in adulthood.


METHODS
A 25-year prospective longitudinal study of the health, development, and adjustment of a birth cohort of 1265 New Zealand children. Measures included assessments of adolescent and young adult cannabis use and ADHD symptoms at age 25, measures of childhood socioeconomic disadvantage, family adversity, childhood and early adolescent behavioural adjustment and cognitive ability, and adolescent and young adult other drug use.


RESULTS
Cannabis use by age 25 was significantly (p<.0001) associated with increasing self-reported adult ADHD symptoms at age 25. Adjustment of the association for potentially confounding factors from childhood and early adolescence reduced the magnitude of the association, but it remained statistically significant (p<.0001). However, control for the mediating effects of other drug use in adolescence and early adulthood reduced the association between cannabis use and adult ADHD symptoms to statistical non-significance (p>.20).


CONCLUSIONS
The current study suggested that the association between cannabis use and adult ADHD symptoms was mediated by other substance use that was associated with cannabis use. The results suggest that cannabis use leads to other drug use, which in turn leads to increased ADHD symptoms. However, it should be noted that the potential influence of such factors as genetic predispositions may still be unaccounted for.
Fergusson
David M
DM
University of Otago, Christchurch School of Medicine and Health Sciences, Christchurch, New Zealand. dm.fergusson@otago.ac.nz
Boden
Joseph M
JM
D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000139:chemically induced / Q000453:epidemiology* / Q000523:psychology; D002186:Cannabinoids / Q000633:toxicity; D015984:Causality; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D006306:Health Surveys; D006801:Humans; D013287:Illicit Drugs / Q000633:toxicity; D008137:Longitudinal Studies; D008297:Male; D002189:Marijuana Abuse / Q000453:epidemiology* / Q000523:psychology; D009520:New Zealand; D011446:Prospective Studies; D012307:Risk Factors; D019966:Substance-Related Disorders / Q000453:epidemiology / Q000523:psychology
D002186:Cannabinoids; D013287:Illicit Drugs