A meta-analytic review of personality traits and their associations with mental health treatment outcomes

Personality traits have been hypothesized to be clinically useful for diagnosis, client conceptualization, treatment planning, as well as for predicting treatment outcomes. Although several studies examined the relation between personality traits and specific therapy outcomes, this literature has not yet been systematically reviewed. Thus, the purpose of the current study was to investigate the relations between personality traits and various therapeutic outcomes. Traits were organized via the domains of the five-factor model to provide a common framework for interpreting effects. Across 99 studies (N = 107, 206), overall findings indicated that traits were systematically related to outcomes, with many specific relations congruent with theorized predictions. Generally, lower levels of neuroticism and higher levels of extraversion, agreeableness, conscientiousness, and openness were associated with more favorable outcomes. More specifically, agreeableness had positive associations with therapeutic alliance and conscientiousness was positively related to abstinence from substances suggesting these traits are likely a beneficial factor to consider at the outset of services. Personality traits also related to various outcomes differently based on moderators. For example, duration of treatment moderated links between traits and outcomes suggesting these effects are amplified over longer services. Overall results suggest that personality assessment can aid with case conceptualization by suggesting potential strengths as well as barriers to treatment.