Affective temperaments mediate the effect of childhood maltreatment on bipolar depression severity.

Aim: Bipolar disorder is a leading disorder contributing to global disease burden, and bipolar depression often becomes severe and refractory. Therefore, clarifying the pathophysiology of bipolar disorder is an urgent issue. Previous reports suggested that factors, such as affective temperaments and childhood maltreatment, aggravate bipolar depression severity. However, to our knowledge, no reports to date have clarified the interrelationship between the above factors and bipolar depression severity. We here hypothesized that childhood maltreatment worsens bipolar depression severity via increasing affective temperaments. To test this hypothesis, a covariance structural analysis was conducted.

Methods: The following information was evaluated for a total of 75 people with bipolar disorder using self-administered questionnaires: demographic characteristics, depressive symptoms (Patient Health Questionnaire-9), history of childhood maltreatment (Child Abuse and Trauma Scale), and affective temperaments (Temperament Evaluation of Memphis, Pisa, Paris, and San Diego Autoquestionnaire). The results were analyzed using covariance structure analysis.

Results: A significant indirect effect of childhood maltreatment on bipolar depression severity via increasing affective temperaments was identified, whereas the direct effect of childhood maltreatment was not significant.

Conclusion: Our results reveal that affective temperaments can mediate the adverse effects of childhood maltreatment on the severity of bipolar depression.