In people with seasonal affective disorder, depression occurs during specific times of the year, typically during the colder, darker winter months. For these patients, the positive effects of light therapy are well-known.
People with this condition typically usually see improvement in symptoms with a combination of light therapy and antidepressants or psychotherapy. Now a study from JAMA Psychiatry has found that light therapy can be an effective treatment for nonseasonal depression as well.
This is the first study to show that nonseasonal depression can potentially be treated with light therapy. Nonseasonal depression is much more common than seasonal depression. It occurs in at least 5 percent of American adults.
For the study, researchers randomly assigned patients between the ages of 19 and 60 to receive one of four treatments for eight weeks. The first group received 30 minutes of daily exposure to fluorescent light. The second group received 20 milligrams of Prozac each day. The third group received both the light and the Prozac, while a fourth control group received a placebo pill and exposure to an electric air purifier.
Using well-validated scales that quantify depression severity, the researchers found improvements in all four groups. The difference between patients who had received Prozac or the placebo pill was not statistically significant. However, light therapy produced significantly more improvement than the placebo alone. When combined, light therapy and Prozac produced the most significant improvements in patients.
Because light therapy can be effectively combined with medicine and psychotherapy without many side effects, researchers believe it could be a good option for safe treatment of multiple kinds of depression in the future.