Cannabis use and Deliberate Self-Harm in Adolescence: a Comparative Analysis of Associations in England and Norway

This study tested hypotheses on causality & selection regarding associations between cannabis use & deliberate self-harm among adolescents. School surveys were conducted among 9,800 adolescents in England & Norway applying identical measures on deliberate self-harm, suicidal thoughts, cannabis use, & various potential confounders. Cannabis use was more prevalent in England than Norway. It was associated with deliberate self-harm, suicidal thoughts, & various risk factors for deliberate self-harm. However, these associations were stronger in Norway than in England. Elevated risk of deliberate self-harm in adolescent cannabis users seems to be mainly due to selection mechanisms. (20 refs.)