Three-way interaction of neuroticism, extraversion, and conscientiousness in the internalizing disorders: Evidence of disorder specificity in a psychiatric sample

•Personality traits interacted when predicting some disorders in a psychiatric sample.•High extraversion, conscientiousness reduced the risk conferred by high neuroticism.•The most consistent effects were for symptoms of major depression.•There was also evidence of trait interactions for PTSD and GAD symptoms.

It is well-established that neuroticism, extraversion, and conscientiousness are individually associated with internalizing disorders, but research suggests that these main effects may be qualified by a three-way interaction when predicting depression. The current study was the first to examine this three-way interaction in a psychiatric sample (N = 463) with a range of internalizing symptoms as the outcomes. Using two omnibus personality inventories and a diagnostic interview, the expected three-way interaction emerged most consistently for symptoms of major depression, and there was also evidence of synergistic effects for post-traumatic stress disorder and generalized anxiety disorder. Findings indicate that, even in a clinically-distressed and currently-disordered sample, high levels of extraversion and conscientiousness protect against distress disorders for those with high levels of neuroticism.