Bright Light Helps 'night Owl' Depression Patients

Researchers at Chinese University said on Thursday that they have developed a new therapy that helps treat some patients with depression - by shining bright light at those who are "night owls" and changing their biological clocks.

The research team recruited 93 patients with depression who often went to bed around 2am and got up after 10am.

Bright light that mimics natural outdoor light was shone at half of the patients for 30 minutes after they woke in the morning every day for five weeks, with the time of day they received the therapy gradually getting earlier and earlier. Dim light was shone at patients in the control group.

Psychiatry professor Wing Yun-kwok said more than 60 percent of patients who underwent the bright light therapy responded better to their medication and their symptoms significantly improved.

He said this was probably linked to an improvement in the patients' sleep and a boost in a chemical in their bodies that helps people feel relaxed and happy.

"There are two possible mechanisms. They shifted their circadian rhythm. The other is the direct effect of the bright light therapy to the biological mechanism of depression, for example, affecting the brain stem nucleus, changing their serotonin balance," he said.

The researchers said experience shows "night owl" patients with depression are less likely to recover and are more likely to commit suicide. They said the bright light therapy can assist medication in treating these patients.