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

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. 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 () 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. 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,  = .019). 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.