The prevalence of marijuana use by adolescents has fluctuated in recent decades, but, overall, has increased significantly. In a study of adolescent health status and risk behaviours among students in grades 7 to 12 in British Columbia, it was found that the patterns of marijuana use had changed, especially among early adolescents. An earlier age of onset of use and an increased frequency of use were noted. The present paper examines the clinical and psychosocial implications of early age of onset of marijuana use, and reports important differences in risky behaviours between users and nonusers. The prevailing attitude that marijuana is a 'safe, recreational' drug is challenged.