Additional 2011 NESARC comorbidity studies are summarized in Table 1. Attention deficit hyperactivity disorder, first assessed at wave 2, was associated with alcohol but not drug disorders [38]. Two studies showed associations of gambling and substance disorders [39,40]. A study showed that men were more likely than women to self-medicate for social anxiety symptoms with alcohol or drugs [41]. Post-traumatic stress disorder, also first assessed at wave 2, was associated with lifetime substance use disorders [42]. Association of trauma exposure and alcohol disorders regardless of post-traumatic stress disorder suggested that the latter did not mediate the relationship between trauma exposure and alcohol disorders [43]. Psychiatric disorders were associated with substance use and also substance disorders among users [44], suggesting that comorbidity was not mediated entirely through use. Finally, drinking circumstances (at home, to self-medicate mood) were related to alcohol and depression comorbidity [45]. A theme from many of these studies is that the field has moved beyond simple association studies, and sought more original designs to understand potential mediators and mechanisms.
