MedicalResearch.com Interview with: Daniel Romer PhD Annenberg Public Policy Center The University of Pennsylvania Philadelphia, PA MedicalResearch.com: What is the background for this study? What are the main findings? Response: Previous research has found some troubling relations between adolescent cannabis use and subsequent increases in conduct problems and other unhealthy consequences.  These studies were done in New Zealand in the late 90’s and we wanted to re-examine those relationships using more contemporary data in the US. We had data on 364 adolescents who were followed from age 13 to 19 in Philadelphia that could provide a more up to date picture of the effects of using cannabis on one important outcome, conduct disorder.  We also wanted to use more sensitive methods than had been used in prior research that would enable us to examine reciprocal relations between cannabis use and c (CP).  That is, it might be the case that youth with CP are prone to using cannabis and that this helps to explain why there appears to be a relation over time between cannabis use and CP rather than cannabis use leading to CP. Our findings supported that hypothesis.  There was no prospective relation between changes in cannabis use and subsequent changes in conduct problems.  Instead, changes in conduct problems were found to predict changes in use of cannabis.  Youth with conduct problems also affiliated more with peers who used cannabis, adding further to their own use.  There was also no evidence that youth who used cannabis sought out peers who used it apart from the effects of CP. Finally, both use of cannabis and  conduct problems predicted subsequent development of a mild cannabis use disorder (CUD).  (more…)