To investigate factors that may influence treatment choice for Bipolar I/II Disorder (BDI/BDII) patients experiencing a major depressive episode.

The HARMONY study (NCT00888264) was a multi-centre, prospective, non-interventional Belgian study that enrolled BDI or BDII patients experiencing a major depressive episode. the study involved four visits (V): V1 (Baseline), V2 (after 6-weeks), V3 (3-months) and V4 (6-months). Data collection included psychiatric hospitalizations, effect of substance abuse or work/school situation on treatment. Safety and tolerability were not assessed.

152 patients aged 19–75 years (mean ± SD: 46.5 ± 11.0; 62.3% female) were recruited: 95 patients (63.3%) with BDI and 55 (36.7%) with BDII, diagnosis was missing for 2 patients. At enrolment, 138 patients were treated by atypical antipsychotics (AAPs) combined with other antipsychotic medications, 14 by AAP monotherapy. Depressive symptoms were treated with quetiapine (42.7%, 64/150), at least one other AAP (40.0%, 60/150; olanzapine, aripiprazole, risperidone or paliperidone), amisulpride (2%, 3/150) and the benzodiazepine chlordiazepoxide (0.67%, 1/150). Patients who first developed symptoms at ≤ 30-years-old were prescribed quetiapine less than patients who developed symptoms when older (34.2%, 27/79 vs. 53.6%, 37/69, p = 0.017). Males were prescribed quetiapine for depressive symptoms more than females (52.6% vs. 36.2%; p = 0.047), more females were prescribed other antipsychotics (42.6% vs. 35.1%). 56.7% (85/150) of patients were hospitalized ≥once for psychiatric symptoms (last 5-years): BDI-63.2% (60/95), BDII-45.5% (25/55). Current treatment choice was not influenced by prior AAP treatment or substance abuse.

Age and gender were the main factors influencing treatment choice for BD patients experiencing a depressive episode.