Objective. A growing body of evidence suggests that undiagnosed and therefore inadequately treated bipolarity may be an important cause of resistance to antidepressant drugs in major depressive disorder. The objective of the study was to assess the utility of Mood Disorder Questionnaire (MDQ) and Hypomania Checklist (HCL-32) in discriminating treatment-resistant and treatment non-resistant patients in a large group of major depressive subjects within the framework of all-Poland multi-center study TRES-DEP.
Methods. One-thousand and fifty-one patients recruited from 150 outpatient psychiatric clinics in Poland and fulfilling DSM-IV criteria for single or recurrent major depressive episode were studied. Five-hundred and sixty-nine patients were identified as having treatment-resistant depression on account of non-obtaining remission in recent depressive episode after minimum of two courses of adequate treatment with antidepressant drugs. They were compared with 482 patients with non-treatment-resistant depression. All patients were assessed using the structured demographic and clinical data interview, as well as the Polish version of MDQ and HCL-32.
Results. Patients with treatment-resistant depression scored significantly higher compared with non-resistant depression both on MDQ and HCL-32 (4.3+3.5 vs 2.7+2.9, and 11.9+8.3 vs 8.5+7.7, respectively). Independent risk factors of treatment resistance were scoring 6 or higher on MDQ or 14 or higher in HCL-32.
Conclusions. Using Polish version of MDQ and HCL-32, we have confirmed the association between bipolarity and worse response to antidepressant drugs in patients with major depressive disorder.