Indirect and direct effects of simultaneous alcohol and cannabis use on alcohol hangovers

Introduction: Simultaneous use of alcohol and cannabis (i.e., using both on same occasion) is a risk factor for heavier drinking and negative alcohol consequences; however, little research has investigated risk conferred for specific negative consequences. One theoretically relevant negative consequence may be alcohol hangovers; however, no studies have tested cross-sectional or prospective relations between simultaneous use and experi-encing alcohol hangovers. Method: The current study (N = 2,964) used public-access data from the National Longitudinal Study on Adolescent to Adult Health (Add Health) to test whether simultaneous alcohol and cannabis use conferred risk for hangover frequency directly or indirectly through heavier drinking. The current study also tested moderated mediation by depressive symptoms, considering simultaneous users have higher levels of depressive symptoms, and depressive symptoms largely mirror those of a hangover. Results: In a cross-sectional model, simultaneous use was associated with more frequent hangovers both directly and indirectly through heavier drinking. In a prospective model, simultaneous use indirectly predicted more frequent hangovers through heavier drinking; however, the direct path was not significant. None of the paths from simultaneous use to drinking or hangovers were moderated by depressive symptoms in either model. Conclusions: The current study suggests that, both concurrently and prospectively, heavier drinking explained significant variance in the relation between simultaneous use and hangover frequency. The significant direct effect of simultaneous use in the cross-sectional model suggests that simultaneous users may have individual characteristics, outside of depressive symptoms, that confer risk for more frequent hangovers above and beyond heavier drinking.