The prevalence of cannabis use we found is broadly similar to that seen in other studies. We are aware of one previous study reporting higher cannabis use among girls compared to boys 31. A consistent finding among our respondents was of higher problem cannabis use among boys. We confirmed the general association between conduct problems and cannabis use found in previous studies, adding evidence of specific nuances of this relationship 4–30. Childhood-limited conduct problems did not appear to be an important risk factor for later cannabis use. Adolescent-onset conduct problems appeared to be more of a risk factor for cannabis use rather than problem use. Early-onset persistent conduct problems, in contrast, appeared to be an important risk factor for problem cannabis use rather than any use.
