Strategic Use of New Generation Antidepressants for Depression

Inclusion Criteria: * non-psychotic unipolar major depressive episode (Diagnostic and Statistical Manual, Fourth Edition \[DSM-IV\]) in the preceding month * age 25-75 * starting treatment with sertraline clinically indicated * tolerability to sertraline 25 mg/d ascertained * can understand and sign informed consent form * can be contacted by telephone for symptom severity and adverse events Exclusion Criteria: * have received antidepressants, mood stabilizers, antipsychotics, psychostimulants, electroconvulsive therapy (ECT) or depression-specific psychotherapies in the preceding month * history of schizophrenia, schizoaffective disorder or bipolar disorder * current dementia, borderline personality disorder, eating disorder or substance dependence * physical disease interfering with sertraline or mirtazapine treatment * allergy to sertraline or mirtazapine * terminal physical illness * currently pregnant or breast-feeding * high risk of imminent suicide * requiring compulsory admission * expected to change doctors within 6 months * cohabiting relatives of research staff * cannot understand Japanese