Concurrent and Sustained Cumulative Effects of Adolescent Marijuana Use on Subclinical Psychotic Symptoms

• NCJ Number: 251333
• Journal: Advances in Life Course Research Volume: 173 Issue: 8 Dated: August 2016 Pages: 781-789
• Author(s): J. Bechtold; A. Hipwell; D. A. Lewis; R. Loeber; D. Pardini
• Date Published: August 2016
• Length: 9 pages
• Grant Number(s): 96-MU-FX-0012
• Sponsoring Agency: Office of Juvenile Justice and Delinquency Prevention (OJJDP)
• Publication Format: Article
• Publication Type: Research (Applied/Empirical); Report (Study/Research); Report (Grant Sponsored); Program/Project Description
• Language: English
• Country: United States of America

Annotation

This study examined whether adolescents who engage in regular marijuana use exhibit a systematic increase in subclinical psychotic symptoms that persist during periods of sustained abstinence.

Abstract

This study stems from concern that adolescents who regularly use marijuana may be at heightened risk of developing subclinical and clinical psychotic symptoms; however, this association could be explained by reverse causation or other factors. The study sample consisted of 1,009 boys who were recruited in 1st and 7th grades. Self-reported frequency of marijuana use, subclinical psychotic symptoms, and several time-varying confounds (e.g., other substance use, internalizing/externalizing problems) were recorded annually from age 13 to 18. Fixed-effects (within-individual change) models examined whether adolescents exhibited an increase in their subclinical psychotic symptoms as a function of their recent and/or cumulative history of regular marijuana use and whether these effects were sustained following abstinence. Models controlled for all time-stable factors (default) and several time-varying covariates as potential confounds. The study found that for each year adolescent boys engaged in regular marijuana use, their expected level of subsequent subclinical psychotic symptoms rose by 21 percent and their expected odds of experiencing subsequent subclinical paranoia or hallucinations rose by 133 percent and 92 percent, respectively. The effect of prior regular marijuana use on subsequent subclinical psychotic symptoms persisted even when adolescents stopped using marijuana for a year. These effects were after controlling for all time-stable and several time-varying confounds. No support was found for reverse causation. These results suggest that regular marijuana use may significantly increase the risk that an adolescent will experience persistent subclinical psychotic symptoms. (Publisher abstract modified)