Abstract: The number of patients with depression across the country is large, leading to significant loss of social labor and high medical costs, which together impose a substantial public health burden. Against the background of high relapse rates and frequent side effects associated with traditional pharmacological interventions, phototherapy modulation technology stands out due to its precision and non-invasive nature. In this review, we explore the multi-level mechanisms of phototherapy modulation in depression from various research perspectives. We also summarize findings from two physical intervention methods—bright light therapy (BLT) and photobiomodulation (PBM)—regarding their effects on non-seasonal depression and related clinical evidence. Finally, we look ahead to a future closed-loop precise photomedicine paradigm based on biofeedback, addressing issues such as standardization of the dose-response relationship and biosafety assessment. This perspective aims to provide theoretical support for the use of phototherapy modulation in treating depression.
Key words: phototherapy; depression; photobiomodulation; bright light therapy; neural circuit
（Acta Laser Biology Sinica, 2026, 35(2): 111-120）