Could a light beam lift depression when drugs fail?

This study tests a non-invasive light therapy called transcranial photobiomodulation (tPBM) on the forehead to help people with treatment-resistant depression. About 40 adults who still have moderate-to-severe depression despite taking antidepressants will receive tPBM at different frequencies. The goal is to see if it reduces depressive symptoms, especially physical complaints like pain or fatigue, and to understand how it affects brain activity.