In addition, we found the influence of both psychiatric comorbidity and genetic risks (CHRNA5-CHRNA3-CHRNB4), were distinct, additive risks for nicotine dependence. There was no evidence to support any significant moderation of the genetic risks for nicotine dependence by the examined comorbid psychiatric disorders. Having alcohol or cannabis dependence, depressive disorder or anxiety disorder did not alter the genetic risk associated with the CHRNA5-CHRNA3-CHRNB4 nicotinic receptor subunit gene cluster for nicotine dependence.
