How does light therapy help treat seasonal depression? - Kelly Rohan (Level 1)

Doctors sometimes give patients an unusual prescription. It is not a pill or a cream. Instead, the doctor tells the patient to use light. This is called light therapy. In winter, the days become short. Animals change their behavior. For example, groundhogs sleep all winter, and some weasels change color. Humans change too. About 1% of people get a sickness called Seasonal Affective Disorder, or SAD. This is a serious type of sadness. It usually happens in the fall and winter. People with SAD feel very tired and sad. They might sleep too much or gain weight. Scientists think this happens because of the body's clock. The brain makes a chemical called melatonin to help us sleep. In winter, people with SAD might make too much melatonin. This makes them feel sleepy all the time. To help, doctors use light therapy. Patients sit near a special bright light every morning. This light tricks the brain. It makes the body think it is summer. This helps people feel happy and awake again.