Depression is a kind of mental illness with high incidence, high recurrence and high disability. But so far, treatment remission rates for depression remain low. Therefore, it is necessary to develop more new treatments. Light therapy has been shown to be effective in treating depression with seasonal patterns. Although most studies have reported that light therapy is also effective in patients with depression without seasonal patterns, high-quality clinical studies are still rare and the conclusions are still controversial. In particular, it remains unclear whether light therapy is effective in treating depression without seasonal patterns in the Chinese population. In addition, there is a lack of biomarkers that predict the efficacy of light therapy.

In conclusion, this study intends to conduct an ADD-ON randomized controlled study to clarify the efficacy and safety of light therapy as synergistic therapy in patients with depression without seasonal patterns, and to screen peripheral biomarkers related to efficacy using transcriptome sequencing technology. It is expected that this study can confirm the effectiveness and safety of light therapy as synergistic therapy, provide an evidence-based basis for the research and exploration of light therapy in Chinese depression population, and provide more options for the synergistic treatment of antidepressants in Chinese depression population.

Inclusion Criteria:

1）Meets DSM-5 criteria for major depressive disorder 2) Age 18-65; 3) HAMD-17 score ≥17; 4) No antidepressants or mood stabilizers were used at least 2 weeks before enrollment; 5) Sign informed consent.

Exclusion Criteria:

1. With seasonal pattern;
2. No previous mental disorders, personality disorders, mental retardation, neurodegenerative diseases, brain trauma, cerebrovascular diseases caused by organic diseases;
3. No previous history of alcohol or substance dependence;
4. Current serious risk of suicide (e.g., previous attempted suicide or recent suicidal behavior); 5）Present with serious, active physical diseases that may interfere with research, including vision problems and photosensitivity disorders; 6）Have received electroconvulsive therapy (ECT or MECT) or transcranial magnetic stimulation (rTMS) in the last 6 months.