Ask Dr. K: Light box therapy can help overcome SAD

DEAR DOCTOR K: I have seasonal affective disorder so I dread the approach of winter. What can I do?

DEAR READER: For some people, the shorter days of this time of year bring on seasonal affective disorder (SAD), also known as winter depression. People with SAD tend to develop symptoms every year. They start gradually in late autumn and build up during the winter months. For many, relief may not come until the longer days of spring.

Only one drug, bupropion (Wellbutrin), is approved for SAD. But selective serotonin reuptake inhibitors (SSRIs) and other antidepressants are also effective.

Another treatment, known as light therapy, is at least as effective for treating SAD as antidepressants. Light therapy involves sitting close to a fluorescent light box for 30 minutes each day. The light is much more intense than the light produced by an ordinary light bulb. Proper light boxes provide 10,000 lux. (The “lux” is a measure of light intensity. By way of comparison, indoor light is about 100 lux. A bright sunny day is 50,000 lux or more.)

Bright white light acts on cells in the eye’s retina. The retina connects to a part of the brain that helps control circadian rhythms of sleep and wakefulness. Scientists believe these rhythms may become disrupted in SAD.

Light treatment is relatively safe and side effects are uncommon.

The U.S. Food and Drug Administration (FDA) does not test, approve or regulate light box devices. Before buying a light box, ask which wavelengths it emits, to avoid any that may be harmful. For example, blue light may be more effective for SAD than full-spectrum white light. Theoretically, certain wavelengths of blue light might damage the retina. However, I’m not aware of any evidence that this occurs with light box therapy.

Finally, a healthy lifestyle, including regular exercise, a good diet and a strong social network, is also likely to help you cope with SAD.