lightThose who experience depression regularly at certain times of the year (in San Francisco, a winter depression usually begins in late October or early November and, depending on where you live, there may be a summer depression linked to heavy fog in July and August) should definitely know about the importance of light exposure in treating depression.

In fact, regular exposure to bright light (being outdoors for an hour and a half on even a grey San Francisco day is usually enough) is the fastest, safest, and least expensive treatment for depression.

My favorite prescription for depression is:

  • 1. Get up every morning by 8 am (more on this later).
  • 2. Get outdoors and exercise (walk) briskly for an hour.

Following this prescription, about half of all my patients experience a significant reduction in depression within a week.

As I was writing this for the first time, I ran across the following from my colleague Ivan Goldberg:

“In addition to psychotherapy and medication, the following are some simple things which will help speed your recovery from depression. The more of them that you can make yourself to do, the faster you are likely to feel better.

  1. Do not remain in bed or sleep for more than 8-hours a day. Over-sleeping has been shown to increase depressed feelings.
  2. Get outside for at least 1/2-hour between 11 AM and 2 PM. Bright light has been shown to have an antidepressant effect. Getting out of doors even on a moderately overcast day gives you the light your require.
  3. Walk briskly, or get some other exercise, for at least 30-minutes every day. Taking a walk out of doors between 11 AM and 2 PM takes care of both your need for bright light and you need for exercise.

Light therapy is definitely an effective antidepressant. A recent review of the literature (Robert Golden, et al, 2005) concluded that a significant reduction in depression symptom severity was associated with bright light treatment (8 studies having an effect size of .84) and dawn simulation in seasonal affective disorder (5 studies ;effect size 0.73) and with bright light treatment with non-seasonal depression (3 studies; effect size 0.53). Bright light as an adjunct to anti-depressant medications for non-seasonal depression was not effective.

The current amount of bright light recommended seems to be approximately 2,500 lux for 2 hours a day or 10,000 lux for 30 minutes a day.

**Effect size refers to the size of the difference between the placebo and active treatment groups. Effect sizes have been categorized along a continuum of no effect (0 to 0.2), low effect (0.2 to 0.5), medium effect (0.5 to 0.8) and high effect (greater than 0.8). The effect size for cognitive therapy of depression, which is one of the most powerful treatments for depression is 0.82. So bright light treatment for seasonal depression is clearly a preferred treatment.”