Models of co-occurring substance misuse and psychosis: are personality traits the missing link?

Traditional models of co-occurring substance misuse in psychosis, including the vulnerability and coping (self-medication) hypotheses, have tended to focus on state-specific factors, such as the severity of substance misuse or psychotic symptoms. In contrast, more recent personality models posit that co-morbidity is related to individual differences in stable trait-specific personality variables that underlie affective outcomes, coping strategies and subsequent risk for substance use. This paper reviews the current evidence base for these three models, and suggests that future research examine the inter-relationships between trait and state-specific personality, affective and behavioural variables on co-morbidity.