Long-Term Effects of Early Adolescent Marijuana Use on Attentional and Inhibitory Control.

Objective: This study sought to examine the prospective effects of early adolescent marijuana use on late adolescent attentional and inhibitory control. Alcohol use, antisocial problems, and gender were included as statistical control variables.

Method: The community sample of 387 adolescents and a caregiver was drawn from a longitudinal study of adolescent substance use that included nine annual assessments. Adolescents were eligible if they were between ages 11 and 12 at recruitment and did not have any disabilities that would preclude them from either understanding or completing the assessment. The sample was evenly split on gender (55% female) and was predominantly non-Hispanic White (83.16%) or African American (9.07%). Attentional and inhibitory control were assessed using parent and adolescent self-reports on the Early Adolescent Temperament Questionnaire-Revised and the Adult Temperament Questionnaire.

Results: Hypotheses were tested using structural equation modeling. High levels of early marijuana use at ages 12-14 significantly predicted low levels of adolescent attentional control at ages 18-21 (β = -.20, p < .05), above and beyond early attentional control, early alcohol use, and antisocial problems.

Conclusions: Findings suggest that marijuana use may adversely affect cognitive development, especially during the sensitive period of early adolescence. Results emphasize the need for further prospective work to investigate relationships between early adolescent marijuana use and the development of executive functioning.