Two of my long-standing patients presented to me recently, both feeling depressed for the previous 2 weeks. The first, a woman in her late 60s, had been on heavy doses of antidepressants for years. She also had delayed sleep phase syndrome (DSPS) and a history of seasonal exacerbations. The second, a man in his 50s, had a long-standing history of bipolar II disorder with winter exacerbations, treated effectively with lithium carbonate and intermittently with light therapy.
One surprising element in the way they reported their symptoms was an absence of any association to the rapidly decreasing photo-period of autumn. I pointed this out to them and suggested a sharp increase in the intensity and duration of their light therapy. In one case, that involved getting a larger new light fixture. In the other, it meant persuading the person with DSPS that she needed to get some light therapy earlier in the day, even if that was difficult given her delayed circadian rhythms. Both responded extremely well to these changes.
The simple lesson here is that modifying antidepressant treatment by adjusting environmental light is often not intuitively obvious, even for those who have suffered for years from seasonal affective disorder (SAD) or chronic depression with winter exacerbations.
In the 4 decades since my colleagues and I first described SAD, I have gleaned and written about many new insights on the syndrome. The optimal use of bright light therapy (BLT) for SAD requires no less skill than the use of antidepressants and mood stabilizers. Simply put, it involves directing the patient to the optimal light fixture for her or him and advising about duration and timing of treatment, as well as how to integrate BLT with other treatment modalities and changing environmental light patterns.
Failure to respond optimally to light as days become shorter and darker, for example, may be corrected in one type of patient by increasing the duration of light therapy to compensate for these changes. Another type of patient — one who tolerates BLT well until the solstice but becomes hypomanic in the spring — can be adequately treated by reducing the duration of light therapy all the way down to 5 minutes or less. In such a person, blue-blocking goggles used at night can also have anti-manic effects.
Finally, it is worth remembering that people with SAD may develop symptoms whenever they are in a light-deprived environment, even in an unseasonable snap of cloudy weather in the spring, for example. Becoming aware of these various considerations will enable you to educate your patients in ways that are not always immediately intuitive to them.
Although the great majority of people with SAD respond to BLT to some degree, only about one-third actually experience remission, even in high-quality clinical trials. Yet, in reviewing my own clinical practice of hundreds of people with SAD over the past 40 years, I was struck by how much higher the remission rate has been in my clinical practice as compared with the standardized trials. I have concluded that the combination of light therapy with other treatment modalities is the key to optimally treating people with SAD, similar to the approach for people with nonseasonal depression.
Such ancillary treatments include cognitive behavior therapy (CBT), antidepressants, diet and exercise, and meditation. In a controlled study of CBT for SAD, Kelly Rohan, PhD, professor of psychology at the University of Vermont, found CBT has a similar level of efficacy as BLT in reducing depression. Interestingly, in the winter following her controlled studies, CBT appeared to be more effective in preventing depressive relapse than BLT.
I interpret these findings to show the importance of teaching patients with SAD the power of using their knowledge about their illness to prevent subsequent relapse. One novel treatment for SAD is the use of high output negative ions, which has been pioneered by Michael Terman, PhD, a psychiatry professor at Columbia University Vagelos College of Physicians and Surgeons in New York City.
It is our duty to help our patients remain healthy and happy through all seasons. People who have trouble with one or more seasons vary from one another and often exhibit patterns that differ from our usual preconceived ideas. For example, winter SAD (as it is sometimes called to differentiate it from people who develop SAD during the summer) generally begins in autumn, and may begin as early as the first week of August in those who are particularly sensitive to the shortening of morning light exposure.
As I mentioned previously, depressive symptoms may emerge at any time of year as a result of light deprivation. Spring and summer may cause other problems resulting in a mixed state of agitated depression, for example. In fact, suicides peak in spring and summer, not in winter, when the retarded and sluggish nature of the depression seems to be a protective factor. Treatment of these variations of seasonal difficulties goes beyond the scope of the present discussion.
In summary, one way for clinicians to think about SAD is to create in your mind — and the patient’s mind — a map of the year in which you and the patient can understand how symptoms vary across the year and how treatments need to be modified accordingly. It can be extremely satisfying to succeed in helping our patients find how they respond to the seasons and other environmental factors.
Norman E. Rosenthal, MD, is a world-renowned psychiatrist, researcher, and best-selling author. He first described SAD and pioneered the use of light therapy as a treatment during his 20 years at the National Institute of Mental Health. He is the author of the new book, Defeating SAD: A Guide to Health and Happiness Through All Seasons.