Evidence for inhibited temperament as a transdiagnostic factor across mood and psychotic disorders

Background: The conceptualization of risk for psychiatric illness is moving from risk factors for specific psychiatric disorders to factors that confer risk for multiple disorders. One potential transdiagnostic risk factor is inhibited temperament, a trait characterized by a fearful or avoidant response to novelty. Inhibited temperament is an established risk factor for anxiety disorders, and evidence suggests inhibited temperament is elevated in schizophrenia, bipolar disorder, and major depressive disorder. Methods: In the current study, we tested the hypothesis that inhibited temperament is a transdiagnostic factor in 490 participants including individuals with schizophrenia (n=184), psychotic bipolar disorder (n=61), major depression disorder (n=53), or no disorders (n=192). Participants completed assessments of temperament, personality, clinical symptoms, cognition, and functioning. An ANOVA was used to test for group differences in inhibited temperament scores. Regressions were used to test whether inhibited temperament scores were associated with the current measures and whether the associations were similar across disorders. Results: Inhibited temperament was similarly elevated in all patient groups compared to controls. Inhibited temperament was similarly associated with anxiety, depression, negative affect, and quality of life across patient groups. Inhibited temperament was not associated with cognition or functional impairment. Limitation: Although the inhibited temperament measure is commonly used, it is a retrospective self-report which may be susceptible to biases. Conclusions: The current study provides evidence that inhibited temperament is a transdiagnostic factor impacting affective systems across mood and psychotic disorders. Inhibited patients may especially benefit from treatments that specifically target anxiety and depression.