Exploring photobiomodulation as a complementary approach for mental health: an integrative review

Mental disorders are a leading cause of disability worldwide, with ongoing challenges in treatment effectiveness. Photobiomodulation (PBM) has emerged as a potential complementary approach for managing mental health conditions. This integrative review aimed to evaluate existing research on PBM in mental health, focusing on treated conditions, outcomes, safety, and research gaps. A systematic search was conducted across six databases: DOAJ, Embase, PubMed, LILACS, Medline, and SciELO. Rayyan^® software was used for article screening, with titles and abstracts independently reviewed by two evaluators using the "Blind on" feature to minimize bias. Included studies were clinical trials and case reports in English, Portuguese, Spanish, Italian, or German. Reviews, non-clinical studies, and those lacking full-text access were excluded. Extracted data included study design, protocol, outcomes, and limitations. Fourteen studies published through July 2025 were included, addressing conditions such as anxiety, depression, and seasonal affective disorder (SAD). PBM showed therapeutic potential, with reported improvements in brain activity, reduced anxiety, and antidepressant effects. Adverse events were infrequent and mild, including headaches, irritability, and difficulty sleeping. However, high variability in protocols-such as wavelength, application sites, and session duration-limits reproducibility and generalizability. PBM appears to be a safe and promising complementary option for mental health, particularly for anxiety, depression, and SAD. To validate its clinical utility, future research should prioritize large-scale, randomized controlled trials with standardized protocols. Additionally, exploring age- and sex-specific responses may support personalized treatment strategies.