Adjunctive Brexpiprazole in Major Depressive Disorder with Inadequate Response to Antidepressants: A Prospective Study

Background: This study evaluated the effects of adjunctive brexpiprazole in adult patients with Major Depressive Disorder (MDD) who experienced an inadequate response to antidepressant therapy. Methods: This 12-week, multicentre, naturalistic, prospective observational study enrolled 60 adults with MDD and an inadequate response to at least two antidepressant treatments. Depressive symptoms, anxiety, clinician-rated illness severity and improvement, functioning, and quality of life were assessed using the Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Clinical Global Impressions—Severity (CGI-S) and —Improvement (CGI-I), Sheehan Disability Scale (SDS), and World Health Organization Quality of Life—Brief Version (WHOQOL-BREF). GAD-7 was assessed only at baseline and week 12. Inferential analyses used complete observations without imputation. Results: Fifty participants (83.3%) completed week 12 and contributed to the principal symptom analyses. Mean PHQ-9 scores decreased from 16.68 ± 5.64 to 11.50 ± 7.30, and GAD-7 scores from 13.32 ± 4.98 to 9.80 ± 5.63 (both p < 0.001). At week 12, PHQ-9 response and remission rates among these 50 participants were 38.0% and 22.0%; corresponding GAD-7 rates were 34.0% and 14.0%. Mean CGI-S decreased from 5.00 ± 1.16 to 3.52 ± 1.79 (p < 0.001); mean week-12 CGI-I was 2.44 ± 1.22. In 43 participants with all three SDS domains recorded at both visits, mean total SDS decreased from 16.79 ± 7.26 to 11.74 ± 8.65 (p < 0.001). Physical, psychological, and social relationship WHOQOL-BREF domains improved, whereas the overall quality-of-life item did not change significantly. Conclusions: In clinical practice, adjunctive brexpiprazole was associated with early improvement in depressive symptoms and improvements in anxiety symptoms, illness severity, psychosocial functioning, and quality-of-life domains.