Millions of people experience depression and lower levels of energy in the winter due to seasonal-affective disorder (SAD), or the “winter blues.” Since the disorder is thought to arise due to a shortage of natural light, one common form of treatment is light therapy, in which the person sits in front of a bright, full-spectrum light at certain times of day. But the effectiveness of light therapy has been unclear, and now researchers from Oulu, Finland, think they know why: light-sensitive regions of the brain may actually play a larger role in SAD symptoms than those in the eyes. For this reason, they’ve designed earphones that shine light through the ear canal to light-sensitive proteins on the brain’s surface, with encouraging results.
