Does Sunlight Actually Put You in a Better Mood?

• Ask Dr. Michael Thase

How big a role does sunlight exposure play in mood? Do light-therapy lamps really help depressed people feel better? If so, what type of light therapy should I look for?

Many people living in temperate climates report that they feel better during the transition from winter to spring, as the days grow longer and sunlight exposure increases. Conversely, a parallel drop in mood is often noted during the transition from fall to winter. 

So it seems likely that sunlight has some natural mood-lifting effects, at least for some people. There are marked individual differences relating to seasonality, however, and the term seasonal affective disorder was coined to describe the subset of people who regularly develop major depressive episodes in the fall or winter that reliably go away or lessen during the spring and summer.

The potential therapeutic effects of bright (full-spectrum) white light have been evaluated in people with such winter depressions, and studies using appropriate control groups indicate significant benefit for these light treatments. The usual daily “dose” of light therapy is 30 minutes of exposure to 10,000 lux (a scientific measurement of the intensity of light) of full-spectrum light; some people do better with longer (60 to 120 minutes) periods of exposure.

It's not necessary to gaze directly into the light, but you should have your eyes open and sit within 3 feet of the light source. Several companies sell “light boxes” that have been developed to reliably deliver the correct dose; the typical cost is about $300. The easiest way to find a light box is to Google “light therapy for seasonal depression."

See the Everyday Health blog "Dr. Z's Medical Report" for more on seasonal affective disorder.
Learn more in the Everyday Health Depression Center.