Cannabis and mental illness in adolescents: a review

Abstract

This article reviews the literature on the association between cannabis exposure and mental illness in adolescents and provides the clinician with an evidence base to address cannabis use with teenagers. Traditionally cannabis was considered a benign recreational drug with low potential for long-term mental health problems and research on its potential therapeutic effects and recent developments to decriminalise cannabis in some American states has sent mixed messages to the public. Early initiation of cannabis use is a risk factor for developing psychosis and is associated with earlier age of onset of psychosis. Whilst the evidence is less robust, adolescent cannabis use is also associated with increased risk for bipolar mood disorders, suicide, anxiety, cognitive and depressive disorders. Early and frequent adolescent cannabis use can be considered as a predictor for mental illness later; and these young users may benefit from early screening and intervention.