CHARACTERISTICS OF ANTIDEPRESSANT CLASSES FOR TREATMENT- RESISTANT DEPRESSION AS DEFINED BY THE NUMBER OF VALID PHARMACOTHERAPIES

Abstract Background Treatment-resistant depression (TRD) is conventionally defined as depression that does not remit with two or more adequate doses of antidepressants of adequate duration (Thase, 1997). Although we have suggested that 3 or more valid pharmacotherapies may include TRD with a high probability, little is known about the characteristics of antidepressants preferred for TRD. Aims & Objectives The purpose of this study was to characterize antidepressant classes for TRD by comparing prescriptions for TRD and non-treatment-resistant depression (non-TRD), classified by the number of valid pharmacotherapies. The study was approved by the Ethics Committee of the Jikei University School of Medicine. Method A longitudinal prescription data set of 494 patients who visited the Department of Psychiatry, The Jikei University Hospital between January 1, 2018 and December 31, 2021 was analyzed. The patients diagnosed with ICD-10 codes F32 (depressive episode) and F33 (recurrent depressive disorder) and treated with antidepressants for 30 days or more were extracted.Patients treated with 3 or more valid pharmacotherapies were included in the TRD group (58 patients) and those treated with 2 or less pharmacotherapies were included in the non-TRD group (436 patients).The presence or absence of antidepressant prescriptions for each group at the last visit during the period was compared using the chi-square test for each class. The significance level was set at 5%. Results The TRD group had significantly higher prescription rates for tricyclic antidepressants and serotonin- noradrenaline reuptake inhibitors (p=3.73×10-5 and 3.22×10-5, respectively), while the non-TRD group had significantly higher prescription rates for selective serotonin reuptake inhibitors (p=1.28×10-2). Prescription rates for noradrenergic and specific serotonergic antidepressants and tetracyclic antidepressants were not significantly different between the two groups (p= 6.14×10-1 and 1.61×10-1, respectively). Discussion & Conclusion It was suggested that in the real-world setting, psychiatrists choose antidepressant classes based on tolerability. References 1. Thase, M. E. and Rush A. J. (1997), “When at first you don't succeed: sequential strategies for antidepressant nonresponders”, J Clin Psychiatry 58: 23–29.