Purpose: The prevalence of bipolar disorder in patients being treated for depression with antidepressants in a family medicine clinic was investigated in this study.
Methods: Adult patients with depression who were treated with an antidepressant in a general outpatient family medicine clinic at the University of Texas were screened for bipolar disorder using the Mood Disorder Questionnaire (MDQ), a brief self-report inventory. A subsample of subjects received the Structured Clinical Interview based on the DSM-IV (SCID) to test the operating characteristics of the MDQ in this population.
Results: of the patients taking an antidepressant for depression, 21.3% screened positive for bipolar disorder on the MDQ. These patients were somewhat younger, more likely to be white, more likely to be living alone, much less likely to be married, and less likely to be employed than those who screen negative. Nearly two thirds of those screened positive had never received diagnosis of bipolar disorder. The sensitivity and specificity of the MDQ in this population, after adjusting for the sampling protocol, were 0.580 (0.454 to 0.706, 95% CI) and 0.930 (0.878 to 0.981, 95% CI) respectively.
Conclusion: Bipolar disorder frequently occurs in patients being treated with antidepressants in primary care settings. Most are unrecognized and undiagnosed. Screening for bipolar disorder in such patients may improve recognition, identification, and appropriate treatment.