Psychotropic Prescribing Patterns Among Bipolar‐I Patients Prior to Established Bipolar‐I Disorder Diagnosis

OBJECTIVE: Bipolar I Disorder (BP-I) is frequently misdiagnosed as Major Depressive Disorder (MDD), delaying appropriate treatment. This study aimed to examine treatment patterns among BP-I patients misdiagnosed with MDD and assess the impact of these regimens on the time until BP-I diagnosis. METHODS: A retrospective cohort study was conducted using the MarketScan Commercial Claims and Encounters database, analyzing 21,771 BP-I patients initially misdiagnosed with MDD and 50,667 correctly diagnosed BP-I patients. Treatment patterns and their influence on time to BP-I diagnosis were assessed using multinomial logistic regression and Cox proportional hazards models. RESULTS: Among the misdiagnosed cohort, 25.1% were initially started on antidepressant monotherapy, with 8.7% continuing this regimen after BP-I diagnosis. In contrast, 7.6% of the initially BP-I diagnosed cohort received antidepressant monotherapy. The time to BP-I conversion was shortest for those on mood stabilizer monotherapy (HR: 1.26, 95% CI: 1.19-1.34, p < 0.001), compared to those on antidepressant monotherapy. After BP-I diagnosis, patients originally misdiagnosed with MDD had different prescribing patterns, exhibiting lower rates of guideline-consistent treatments. Specifically, patients initially diagnosed with BP-I were more likely to receive mood stabilizing therapy, either as monotherapy (OR = 2.63, p < 0.001) or in combination with an antidepressant (OR = 1.84, p < 0.001). CONCLUSION: Misdiagnosis of BP-I as MDD leads to significant delays in accurate diagnosis and inappropriate treatment regimens, highlighting the critical need for improved diagnostic accuracy at initial presentation. Prompt and accurate BP-I diagnosis can optimize treatment approaches and improve patient outcomes.