With the recent discovery of specific genetic variants for nicotine dependence, this study examined the joint contribution of comorbid psychiatric disorders and genetic risks to nicotine dependence. Importantly, we tested if the genetic variants for nicotine dependence were also associated with other commonly comorbid psychiatric disorders (pleiotropy), and if other psychiatric disorders moderated these known genetic risk for nicotine dependence. The strength of our study lies in the specific case control design contrasting the difference between being a smoker to becoming nicotine dependent, the assessments of DSM-IV diagnoses of other psychiatric disorders, and the opportunity to characterize identified genetic findings.
