Co-occurring psychiatric diagnoses have a negative impact on quality of life and change the presentation and prognosis of bipolar disorder (BD). To date, comorbidity research on patients with BD has primarily focused on co-occurring anxiety disorders and trauma history; only recently has there been a specific focus on co-occurring PTSD and BD. Although rates of trauma and PTSD are higher in those with bipolar disorder than in the general population, little is known about differences across bipolar subtypes.
Using the NIMH STEP-BD dataset (N=3158), this study evaluated whether there were baseline differences in the prevalence of PTSD between participants with bipolar disorder I (BDI) and bipolar disorder II (BDII), using the MINI and the Davidson Trauma Scale. Differences in PTSD symptom clusters between patients with BDI and BDII were also evaluated.
A significantly greater proportion of participants with BDI had co-occurring PTSD at time of study entry (Χ2(1)=12.6; p<.001). BDI and BDII subgroups did not significantly differ in re-experiencing, avoidance, or arousal symptoms.
The analysis may suggest a correlational relationship between PTSD and BD, not a causal one. Further, it is possible this population seeks treatment more often than individuals with PTSD alone. Finally, due to the episodic nature of BD and symptom overlap between the two disorders, misdiagnosis is possible.
PTSD may be more prevalent in patients with BDI. However, the symptom presentation of PTSD appears similar across BD subtypes. Individuals should be thoroughly assessed for co-occurring diagnoses in an effort to provide appropriate treatment.