BACKGROUND: Major depressive disorder (MDD) is a common, debilitating disorder with substantial socioeconomic burden. Many patients with MDD experience symptoms that impair functioning and productivity, often negatively affecting work or educational pursuits. This Phase 3b open-label study evaluated adjunctive brexpiprazole in young adults with MDD, who were in work or study. METHODS: Young patients (18-35 years) with MDD (inadequate responders to 1-3 antidepressant treatments [ADT] for their current episode) received brexpiprazole 1-3mg/day (target dose, 2mg/day) adjunctive to the same stable dose of ADT for 12 weeks. RESULTS: Depressive symptoms improved during treatment with adjunctive brexpiprazole (primary endpoint, least squares [LS] mean change from baseline in Montgomery-Åsberg Depression Rating Scale [MADRS] total score, -18.1 [p<0.0001]). Reductions from baseline in Sheehan Disability Scale Score (SDS; LS mean change -11.2 [p<0.0001]) and Work Limitations Questionnaire (WLQ; p<0.0001) indicated improvements in the effects of patients' symptoms on functioning (work/school, social life, and home responsibilities). Changes from baseline in additional measures supported improvements in patient functioning and depression symptoms. The most common adverse events were headache (21.3%), weight increase (17.0%), and somnolence (17.0%); reported rates of akathisia were low (6.4%). Clinically relevant increases in weight (≥7%) occurred in 10.5% of patients. LIMITATIONS: Open-label design; absence of comparator. CONCLUSIONS: Brexpiprazole may represent an effective therapy for adjunctive treatment strategy of young adults with MDD who are working or studying. The observed improvements in work/school functioning in patients with MDD, whose depression was treated with ADT+brexpiprazole, suggests potential to reduce socioeconomic burden.