Transcranial Photobiomodulation (tPBM) for Major Depressive Disorder

Major depressive disorder (MDD) is a leading cause of disability worldwide with current FDA approved treatments often not providing sustained relief to patients. Transcranial photobiomodu-lation (tPBM) with near-infrared light (NIR) is a neuromodulation technique that affects mitochondrial metabo-lism and has shown beneficial clinical outcomes in neurological and psychi-atric disorders. At the cellular level tPBM causes various effects including increased oxygen consumption, in-creased adenosinetriphosphate (ATP) production, and short bursts of reac-tive oxygen species (ROS). Decreasing oxidative stress through lowering the secondary production of ROS, and in-creasing neural connectivity, through boosting of neurogenesis and synap-togenesis, as well as increasing energy metabolism are putative mechanisms for tPBM antidepressant effect. Pre-liminary clinical trials have shown that NIR tPBM is effective at decreasing symptoms of depression compared to sham, however optimal dosimetry is still uncertain. In some reports, the antidepressant effects of tPBM were sustained after treatment discontinua-tion. Choice of adequate treatment pa-rameters is likely critical to the effi cacy and tolerability of tPBM for MDD. Gen-eral conclusions can be drawn to guide clinicians to the off-label use of tPBM for MDD in clinical practice. [Psychiatr Ann. 2022;52(11):466-471.]