The Efficacy of Probiotic Compared With Placebo Commitment Therapy for Treatment of Major Depressive Disorder

1. To assess the differences in quality of life among patients on probiotic, placebo and ACT via the use of questionnaire, at 4 timelines (baseline, 6 weeks after starting intervention, 12 weeks after starting intervention, and 24 weeks after starting intervention which is 12 weeks post-termination of intervention). 2. To assess the differences in blood biological markers such as BDNF, TNF-α, IL-6, IL-1β, CRP, and VEGF among patients on probiotic, placebo and ACT via blood biochemical analyses, at 4 timelines (baseline, 6 weeks after starting intervention, 12 weeks after starting intervention, and 24 weeks after starting intervention which is 12 weeks post-termination of intervention). 3. To assess the differences in gut microbiota profiles of patients on probiotic, placebo and ACT via the use of fecal samples, at 3 timelines (baseline, 12 weeks after starting intervention, and 24 weeks after starting intervention which is 12 weeks post-termination of intervention).