How SAD Affects Bipolar Disorder
About 20 percent of bipolar patients experience a mood shift based on seasonal sunlight. Learn about seasonal bipolar disorder and how to cope with it.
As many as 20 percent of bipolar disorder patients can track their moods by looking at the calendar: If winter is coming on, they can expect to have seasonal depression. If it’s spring, they might experience mania or hypomania.
“This seasonal component is related to the amount of sunlight,” says Melvin McInnis, MD, director of psychiatry programs at the University of Michigan Depression Center in Ann Arbor. “In the wintertime, people are more depressed. The patient says, ‘Every January, I start to go down.’ Then in the spring, the amount of sunlight destabilizes their mood to the point of them becoming manic and hypomanic. We [doctors] often refer to the ‘manic month of May.’”
Seasonal Affective Disorder vs. Seasonal Bipolar Disorder
Doctors have long distinguished between seasonal depression and seasonal bipolar disorder. Commonly referred to as SAD or seasonal affective disorder, seasonal depression is a mood disorder brought on by the biological effects of a lack of sunlight. Typically experienced in the late fall and winter, it is particularly prevalent in northern regions.
What distinguishes seasonal bipolar disorder from SAD is the presence of a manic episode within a given period of time.
“What happens historically is that we ask patients and we ask family members if they’ve also seen signs or symptoms of a manic or hypomanic episode, thereby qualifying bipolar mood disorder,” says psychiatrist David J. Muzina, MD, vice chair for research and education and associate professor of medicine in the department of psychiatry and psychology at the Cleveland Clinic in Ohio. “If we don’t find that past history, then that person who has the seasonal winter response only has a depressive disorder.”
Seasonal Shifts in Mood: Who Is Affected?
Why do some patients experience a seasonal component to their bipolar disorder and others don’t? One of the most prominent developing theories has to do with circadian rhythms — the “biological clock” — the body’s internal, rhythmic response to changes in a 24-hour day, especially sunlight. This response is controlled by a complex set of genes commonly referred to as “clock genes.” If only some of these genes are abnormal, you could develop seasonal bipolar disorder.
“This is a subset of pattern within the overall population,” says Dr. Muzina. “We guess people with seasonal disorder have some genetic predisposition because of problems within those clock genes.”
Bipolar Disorder and Seasonal Depression: Treatment Options
If you and your doctor determine that your bipolar disorder has a seasonal component, he or she may suggest various treatment options, particularly related to depressive episodes, which tend to be more severe for the patient with seasonal bipolar disorder:
- Movement, meditation, and therapy. If the depression is mild, you may not need additional medication. Rather, you may be able to manage your depression with yoga, talk therapy, meditation, and exercise, and by maintaining the same routine every day, especially related to sleeping and waking.
- Light therapy. Light therapy, such as special light boxes used 30 minutes a day, can be helpful. But light therapy must be used carefully. “Light therapy has the potential of inducing a manic reaction in the person with bipolar disorder,” says Muzina. “Too much bright light can turn a person from being depressed to hypomanic or manic or rapid-cycling, going from highs to lows very quickly.”
- Melatonin. If the depression is severe, light therapy may be indicated in combination with additional medications, such as melatonin. Melatonin, a naturally occurring chemical transmitter that helps regulate circadian rhythms, has been long used in synthetic form to reset the abnormal clock for people suffering from jet lag or insomnia.
The good news about seasonal bipolar disorder relates to the management of your symptoms. Unlike some patients with bipolar disorder, you can anticipate the coming of your mood shift simply by watching the calendar. You and your care team can be prepared with a solid treatment plan in hand.
Last Updated: 09/25/2009