Interpersonal Trauma and Depression Severity Among Individuals With Bipolar Disorder: Findings From the Prechter Longitudinal Study of Bipolar Disorder

Background: Experiences of interpersonal trauma, both in childhood and in adulthood, can affect the trajectory of bipolar disorder (BD). However, the degree to which childhood and/or adult trauma impacts the longitudinal trajectory of depression severity among individuals with BD actively receiving treatment remains unclear. Methods: The effects of childhood trauma (Childhood Trauma Questionnaire) and adult trauma (Life Events Checklist) on depression severity (Hamilton Depression Rating Scale) were investigated in a treatment-receiving subsample with BD (DSM-IV) of the Prechter Longitudinal Study of Bipolar Disorder (2005-present). A mixed-effects linear regression model was used to assess the trajectory of depression severity over 4 years. Results: Depression severity was evaluated in 360 participants, of whom 267 (74.8%) reported a history of interpersonal trauma. A history of childhood trauma alone (n = 110) and childhood and adult trauma combined (n = 108)-but not adult trauma alone (n = 49) -were associated with greater depression severity at the 2-year and 6-year follow-up assessments. However, the trajectory of depression severity (ie, change over time) was similar between participants with a history of childhood trauma, those with a history of adult trauma, and those with no history of interpersonal trauma. Interestingly, participants with a history of both types of trauma showed more improvement in depression severity (ie, from year 2 to year 4: β = 1.67, P = .019). Conclusions: Despite actively receiving treatment for BD, participants with a history of interpersonal trauma-particularly childhood trauma-presented with more severe depressive symptoms at several follow-up assessments. Hence, interpersonal trauma may represent an essential treatment target.