Causes,
avoidance,
and treatment
with bright
light therapy

More on Seasonal Affective Disorder

From “Seasonal Affective Disorder (SAD): About Light, Depression and Melatonin,” by Gila Lindsley, Ph.D., A.C.P.

Seasonal Affective Disorder (SAD) may be identified by a number of symptoms, including depression, sadness, anxiety, irritability and violence, decreased physical activity, increased appetite (often with cravings for carbohydrates) and hypersomnia – sleeping for very long hours.

Symptoms of SAD typically surface in the winter months, and were initially linked to the onset of the holidays and feelings of aloneness many people experience at that time of year. Scientists later identified predictable patterns that directly correlated to the number of daylight hours in a given day.

“As daylight began noticeably decreasing in September,” writes Dr. Lindsley, “some people were affected. By the time the days bracketing the winter solstice came, almost everyone in the study group was affected. Then, as the season moved away from the solstice toward spring with lengthening daylight hours, the number of affected people began to decline. By the end of May, almost everyone was back to their old selves, some unfortunately even switching into what psychiatrists call mania.”

To support their theory of SAD symptoms being linked to hours of daylight, scientists supplied light to see if it would reverse the effects of SAD. While dimmer, yellow light produced no effect, bright lights with a frequency spectrum simulating that of sunlight did reverse the effects of SAD for most patients. Further evidence has since accumulated to support the theory that decreased daylight produces SAD in affected individuals. There is even suggestion that the timing of Christmas, Hannukah and other “festivals of light” have less to do with specific dates of historical events tied to these holidays, and more to do with the cycle of seasons – “lighting up the spirits during the darkest days.”

Tips for avoiding SAD

• Pay attention to your mood and energy level. If you notice your spirits sinking at the end of the summer, take pre-emptive action.
• Plan active events in advance of the fall.
• Expose yourself to as much bright light as you can. If it is sunny, go outside as much as possible. If it is overcast, use as much light indoors as you can.
• Stay physically active.
• Establish a mindset that will help you enjoy the winter months.
• If you feel yourself sinking and realize you are losing control, seek competent professional help.
  

Bright Light Therapy

• Bright Light Therapy (BLT) is the most established treatment for SAD.
• BLT consists of looking at special broad spectrum bright lights from one-half to three hours per day, generally in the early morning. To avoid possible eye damage, do not stare directly into the lights.
• A substantial amount of light is required, which means the distance from the lights to your eyes should be monitored. The distance should be small enough to provide the best amount of light, but large enough so as not to damage the eyes.
• Timing and length of daily exposure are highly individual.
• BLT is unlikely to help in certain situations because depressed mood is not always related to a decreased number of daylight hours. There are many other sources of depressed mood which are unrelated to light exposure.
• If a few days of light trial do not improve your depression, seek other help.
• Light sources are available commercially.

Original editor’s note:

Symptoms of depression should be taken very seriously. Proper diagnosis is essential to treatment. Where sleep disorders and seasonal factors are a possible factor (SAD, sleep apnea), you may need support and professional help. It should be clear that the use of bright light therapy should be under the direction of a qualified professional.