Light therapy works by simulating natural sunlight with full- spectrum light during the darker winter months. Light boxes encourage the brain to reduce the production of melatonin ( the hormone that makes you sleepy) and increase the production of serotonin ( the hormone related to mood). A meta- analysis published in The American Journal of Psychiatry found that light therapy demonstrated a signifi cant eff ect on seasonal aff ective disorder. Benefi ts included increased energy, improved mood, decreased depression, and better sleep. Try using a light box every day for 30 minutes, ideally in the morning, to see the results for yourself.