What is it?
Light therapy involves exposure to bright light for around 2 hours each day, usually in the morning.
How does it work?
Light therapy is mainly used for people who tend to become depressed in autumn and winter, when the daylight is shorter. These people then get better in spring and summer. This type of depression is knows as seasonal affective disorder (SAD). The lack of light in winter is thought to affect their natural body rhythms.
Is it effective?
There is good evidence that light therapy helps people with winter depression. It works better than placebos (treatments with no known effect) and as well as antidepressant drugs. The therapy works best if given early in the morning rather than later in the day. There is less evidence on whether light therapy helps people whose depression is not seasonal. However, the small number of studies show that it could be beneficial.
Are there any disadvantages?
Light therapy can produce mild mania (over-excitement) in some people. Problems in getting to sleep at night have also been sometimes found. Light therapy is associated with fewer side effects than medication.
Where do you get it?
Light therapy usually involves sitting in front of a bank of bright fluorescent lights. Equipment such as light boxes and dawn simulators are available to buy over the Internet. However, except in countries that have very short winter days, you can get the necessary light exposure by a 1 or 2 hour walk outside in the morning, even on overcast winter days.
Light therapy is one of the best treatments for seasonal depression and may also be helpful for other types of depression.
- Lam RW, Levitt AJ, Levitan RD, Enns MW, Morehouse R, Michalak EE, et al. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. Am J Psychiatry. 2006 May;163(5):805-12.
- Nussbaumer, B., Kaminski-Hartenthaler, A., Forneris, C. A., Morgan, L. C., Sonis, J. H., Gaynes, B. N., Gartlehner, G. (2015). Light therapy for preventing seasonal affective disorder. Cochrane Database of Systematic Reviews(11).
- Tuunainen A, Kripke DF, Endo T. Light therapy for non-seasonal depression (Cochrane Review). In: The Cochrane Library, Issue 3, 2004. Chichester, UK: John Wiley & Sons, Ltd.
- Wirz-Justice A. Beginning to see the light. Archives of General Psychiatry 1998; 55: 861-862.
Last reviewed and updated: 1 December 2016