Transcranial Photobiomodulation with Near-Infrared Light for Generalized Anxiety Disorder: A Pilot Study

<b><i>Objective:</i></b> Our aim was to test the anxiolytic effect of transcranial photobiomodulation (t-PBM) with near-infrared light (NIR) in subjects suffering from generalized anxiety disorder (GAD). <b><i>Background:</i></b> t-PBM with NIR is an experimental, noninvasive treatment for mood and anxiety disorders. Preliminary evidence indicates a potential anxiolytic effect of transcranial NIR. <b><i>Methods:</i></b> Fifteen subjects suffering from GAD were recruited in an open-label 8-week study. Each participant self-administered t-PBM daily, for 20 min (continuous wave; 830 nm peak wavelength; average irradiance 30 mW/cm²; average fluence 36 J/cm²; total energy delivered per session 2.9 kJ: total output power 2.4 W) broadly on the forehead (total area 80 cm²) with an LED-cluster headband (Cerebral Sciences). Outcome measures were the reduction in total scores of the Hamilton Anxiety Scale (SIGH-A), the Clinical Global Impressions-Severity (CGI-S) subscale and the Pittsburgh Sleep Quality Index (PSQI) subscales from baseline to last observation carried forward. <b><i>Results:</i></b> Of the 15 recruited subjects (mean age 30 ± 14 years; 67% women), 12 (80%) completed the open trial. Results show a significant reduction in the total scores of SIGH-A (from 17.27 ± 4.89 to 8.47 ± 4.87; <i>p</i> < 0.001; Cohen's <i>d</i> effect size = 1.47), in the CGI-S subscale (from 4.53 ± 0.52 to 2.87 ± 0.83; <i>p</i> < 0.001; Cohen's <i>d</i> effect size = 2.04), as well as significant improvements in sleep at the PSQI. t-PBM was well tolerated with no serious adverse events. <b><i>Conclusions:</i></b> Based on our pilot study, t-PBM with NIR is a promising alternative treatment for GAD. Larger, randomized, double-blind, sham-controlled studies are needed.