Bright light therapy for the aged depressed: Study

By Dr. Ananya Mandal, MDJan 5 2011

A new study shows that exposure to bright light may ease symptoms of depression in elderly people. The researchers tried three weeks of bright light therapy using specially designed light boxes and saw that it improved symptoms of depression by as much as 54% in older adults with depression. The light therapy also improved sleep and optimized levels of the neurotransmitter serotonin. Low levels of serotonin are associated with depression and often targeted by antidepressant drugs. This is the first study of its kind to show a beneficial effect of bright light therapy on treating depression in the elderly with non-seasonal major depressive disorder.

Ritsaert Leiverse of the department of psychiatry at VU University Medical Center in Amsterdam, the Netherlands, and colleagues said, “Bright light treatment may provide a viable alternative for patients who refuse, resist, or do not tolerate antidepressant treatment.” The study appeared in the Archives of General Psychiatry.

It is well known that depression in the elderly leads to sleep problems and other symptoms because of a disruption of the body's natural circadian rhythms or body clock. These rhythm disturbances are seen more commonly among the elderly who expose themselves less frequently to bright environmental light.

For the study the team evaluated the effects of three weeks of bright light therapy in 89 adults over age 60 diagnosed with depression. They were randomly divided into two groups and exposed to either an hour of bright pale blue light therapy or dim red light treatment (placebo treatment) from a light box at home during the early morning hours. After the three weeks reports showed that those on bright light therapy improved depressive symptoms by 43%, compared with the 36% improvement found with the placebo treatment. Even after three weeks therapy symptoms of depression continued to improve among the bright light therapy group (54% improvement vs. 33% in the placebo group). There was also a decrease in levels of the stress hormone cortisol among people who received bright light therapy. Sleep quality also improved among the bright light therapy group. The Dutch team’s results held up even when they controlled for whether and how often the participants had used antidepressants, how old they were, what their gender was, and when their depression first began.

David Ames, the director of the National Ageing Research Institute in Melbourne, said about one in 100 elderly people were depressed enough to need treatment from a psychiatrist, while 15 per cent had milder forms of the illness. He added, “Some forms of depression do have some characteristics of circadian disturbance.” Further research should compare light therapy with antidepressants, Professor Ames said. If it proved effective, bright light would be “reasonably non-toxic” and inexpensive.