This significant effect of CUD on other SUDs is confirmed by the statistical moderation effects. In this model, a significant indirect effect of CUD (0.44) was found on the relationship between bipolar disorders and number of other alcohol and SUDs. No such effect was detected for CUD on the relationship between bipolar disorders and any other comorbid mental disorders. Thus, comorbid CUD influence significantly the liability for comorbid other SUDs. Certainly, beside genetic factors, other biological and psychosocial mechanisms behind this relationship need to be elucidated in subsequent research.
