Major depressive disorder is a serious, recurrent and disabling mental disorder, which is the second leading cause of years lost to disability worldwide. Accumulating evidence suggests the important role for inflammation and oxidative stress in the pathophysiology of depression. Sulforaphane extracted from broccoli sprout is an agent with potent anti-oxidant and anti-inflammatory activity. Previous studies suggested sulforaphane activates Keap1-Nrf2 system to prevent depression-like phenotype in mice. In this study, the investigator attempts to evaluate the efficacy, safety, and tolerability of sulforaphane plus a fixed oral antipressant in adult participants diagnosed with depression.

A total of 90 patients aged 18-55 years with depression will be included, all of whom gave informed consent. Participants will receive 12 weeks of either sulforaphane or placebo per day, in addition to the existing treatment. Baseline assessments include demographics, a comprehensive medical history, anthropometric measurements (weight and height), physical examination, and lab work. Clinical symptoms will be assessed by the Montgomery-A° sberg Depression Rating Scale (MADRS), Hamilton depressive scale (HAMD), Hamilton Anxiety Scale(HAMA), and Patient Health Questionnaire-9 (PHQ-9). The safety will be assessed by Treatment Emergent Symptom Scale (TESS). The cognitive function will be evaluated by MATRICS Consensus Cognitive Battery （MCCB）at the beginning of the study and at week 12. The cranial MRI is examined at baseline and repeated at week 12. The primary outcomes will be the effective time and the percentages of efficacy at 8 weeks, measured using the MADRS. Efficacy is defined as ≥50% decreases in the total score of MADRS. Secondary outcomes include global psychopathology, quality of life, functioning, cognition, biological data, safety and tolerability.

Inclusion Criteria:

• 18-55 years old
• Clinical diagnosis of recurrent MDD or single-episode MDD with MADRS≥22, CGI-SI≥4
• be adherent to the continued oral antidepressant treatment medication

Exclusion Criteria:

• treatment-resistant depression
• have known allergies, hypersensitivity, intolerance, or contraindications to SSRI or any of the trial preparations
• strong homicidal ideation/intent
• pregnancy

Participants and researchers are blind to treatment allocation (double-blind). An independent researcher developed the computer-generated randomization plan.