Transcranial Photobiomodulation for the Treatment of Major Depressive Disorder. The ELATED-2 Pilot Trial.

Objective: Our objective was to test the antidepressant effect of transcranial photobiomodulation (t-PBM) with near-infrared (NIR) light in subjects suffering from major depressive disorder (MDD). Background: t-PBM with NIR light is a new treatment for MDD. NIR light is absorbed by mitochondria; it boosts cerebral metabolism, promotes neuroplasticity, and modulates endogenous opioids, while decreasing inflammation and oxidative stress. Materials and methods: We conducted a double-blind, sham-controlled study on the safety and efficacy (change in Hamilton Depression Rating Scale [HAM-D-17] total score at end-point) of adjunct t-PBM NIR [823nm; continuous wave (CW); 28.7x2cm(2); 36.2mW/cm(2); up to 65.2J/cm(2); 20-30min/session], delivered to dorsolateral prefrontal cortex, bilaterally and simultaneously, twice a week, for 8 weeks, in subjects with MDD. Baseline observation carried forward (BOCF), last observation carried forward (LOCF), and completers analyses were performed. Results: The effect size for the antidepressant effect of t-PBM, based on change in HAM-D-17 total score at end-point, was 0.90, 0.75, and 1.5 (Cohen's d), respectively for BOCF (n=21), LOCF (n=19), and completers (n=13). Further, t-PBM was fairly well tolerated, with no serious adverse events. Conclusions: t-PBM with NIR light demonstrated antidepressant properties with a medium to large effect size in patients with MDD. Replication is warranted, especially in consideration of the small sample size.