There is an emerging literature focused on the correlates of cannabis use in BD, with some evidence that cannabis users are more likely to be male, to abuse alcohol and other substances, to experience greater overall illness severity, and to evidence poorer treatment adherence when compared to non-users [8–10]. Particularly alarming, cannabis use in BD has also been associated with significantly increased risk for new onset [10–15] and longer duration [9,16,17] of manic episodes, as well as incidence of psychosis [8,10]. Data have also revealed a dose-response relationship between the degree of cannabis use and first onset of BD, with heavier users (i.e., > 10 times within one month lifetime) reporting significantly earlier age of disorder onset compared to non-users [18].
