Objective: Prior studies of the association between neurocognitive functions and marijuana use among adolescents are mostly cross-sectional and conducted in adolescents who have already initiated marijuana use. The current study used a longitudinal design on a preadolescent, substance-naive sample. We sought to identify demographic factors associated with neurocognitive functions and the complement of neurocognitive function characteristics that predict marijuana initiation in adolescents.
Method: Substance-naive adolescents (n = 465) ages 10-12 years (51% male) were recruited from a community with high levels of adolescent marijuana use and prospectively followed to ages 12-15. Tasks measuring neurocognitive functions were administered and audio-assisted interviews were conducted. Two types of models were estimated for each outcome: forced-entry models and another using stepwise selection via bidirectional elimination with varying tolerance levels to account for selection misspecification.
Results: About 10% (n = 49) initiated marijuana use over the study period. Child's age, academic achievement, and parental education were associated with baseline neurocognitive functions; namely, positive emotion attributions and lower impulsivity. Facial recognition-particularly misattribution of sad faces-was the strongest predictor of marijuana initiation, including in the stepwise model (partial OR = 1.3, 95% CI [1.03, 1.63], p < .05) that resulted in the best-fitting model.
Conclusions: Prediction of marijuana initiation was improved in stepwise models compared with forced-entry models. Emotion perception appears to be an early developmental risk factor that is prospectively associated with marijuana initiation; as expected, other neurocognitive functions did not play an interactive role. Future studies of the interrelationships between emotion perception and the myriad other factors implicated in marijuana initiation, including neurocognitive functions not measured here, will provide a more comprehensive understanding of risk for marijuana initiation.