Pharmacotherapy in Comorbid Bipolar Disorder and Post-Traumatic Stress Disorder From the STEP-BD Cohort

Post-traumatic stress disorder (PTSD) is more prevalent in those with bipolar disorder (BD) than in the general population, with rates of PTSD as high as 55% in some BD cohorts. Despite this, little research explores the effects of pharmacotherapy treatments in those with comorbid BD and PTSD. This study aims to explore patterns of pharmacotherapy use at baseline and their impact on symptoms in individuals with BD alone and comorbid BD and PTSD.

The Systematic Treatment Enhancement Program for BD (STEP-BD) cohort was utilised to examine and compare BD symptoms and pharmacotherapy treatments between those with BD alone (n = 3393) and those with comorbid BD and PTSD (n = 304). We conducted regression models to compare those with and without comorbid PTSD. Models included measures of depression, mania, functioning and quality of life over 24 months of the STEP-BD study. We included baseline pharmacotherapies (lithium, valproate, antidepressants, antipsychotics and benzodiazepines) as predictor outcome variables in all models.

At baseline, reported use of lithium was lower in the comorbid BD and PTSD group, while the use of antidepressants, antipsychotics and benzodiazepines was significantly higher in the comorbid BD and PTSD than in the BD alone group. Benzodiazepine use was associated with a small improvement in depression symptom scores and poorer quality of life in those with comorbid BD and PTSD. Lastly, those with comorbid PTSD experienced higher levels of mania and depression symptoms and lower functioning and quality of life compared to BD alone, irrespective of pharmacotherapy treatment.

Clinical trial participants with BD and PTSD reported worse symptoms and outcomes across 24 months of the STEP-BD study compared to those without comorbid PTSD, regardless of baseline medication use. These results highlight the importance of considering comorbidity in the treatment of mental health conditions, specifically BD, and the need for further exploration of effective treatment options.