Decreased core symptoms of mania and utilization of lithium/mood stabilizing anticonvulsants in US bipolar I patients of African vs European ancestry

Objective: Misdiagnosis is common in bipolar disorder and disproportionally affects racial and ethnic minorities. There is interest in better understanding the contribution of differential symptomatic illness presentation to misdiagnosis. Methods: Utilizing the Genetic Association Information Network (GAIN) public database, this study compared clinical phenomenology between bipolar patients of African vs European ancestry (AA = 415 vs EA = 480). The Diagnostic Interview for Genetic Studies (DIGS) was utilized to evaluate symptom endorsement contributing to diagnostic confirmation of bipolar I disorder (BPI) and lifetime medication use. Results: Elevated/euphoric mood was less endorsed in AA vs EA participants (p = 0.03). During the most severe episode of mania, AA participants, in comparison to EA participants, had a lower sum of manic symptoms (p = 0.006) and a higher rate of hallucinations (p = 0.01). During lifetime psychosis, AA participants, in comparison to EA participants, had a higher lifetime sum of delusions (p = 0.01) and hallucinations (p < 0.0001). AA participants reported lower use of lithium (p < 0.0001) and mood stabilizing anticonvulsants (p = 0.0003). Conclusions: The differential rate of manic and psychotic symptom endorsement from a semi-structured diagnostic interview may represent differential illness presentation based on biological differences or racial or study biases (e.g. ascertainment). Increased minority recruitment in bipolar research is therefore a necessary future direction. Limitations: Recall and interviewer bias may affect study results, but are likely diminished by the alignment of symptom endorsement and medication use.