From the American Psychological Association:

During the darker days of winter, more people report feeling depressed and tired. For many, it’s a normal response to less sunlight, but for others, it can be a clinical form of depression called seasonal affective disorder.

To help understand the difference between the winter blues and SAD, APA asked psychologist and SAD expert Kelly Rohan, PhD, to explain the signs of the disorder and potential treatments.

Rohan is an associate professor of psychology at the University of Vermont. Her area of interest is adult mood disorders with specialization in cognitive-behavioral therapy and theory of depression and SAD. Her most recent project is a National Institutes of Mental Health-funded clinical trial comparing SAD patients who were treated with light therapy to those treated with cognitive-behavioral therapy. 

APA: What is seasonal affective disorder and how is it different from winter blues or other types of depression?

Dr. Rohan: Seasonal affective disorder is a regular seasonal pattern of major depressive episodes during the fall and winter months with periods of full improvement in the spring and summer. The symptoms of SAD are exactly the same as non-seasonal depression symptoms, which can include a loss of interest or pleasure in normally enjoyed activities, excessive fatigue, difficulty concentrating, a significant change in sleep length and thoughts about death or suicide. The only difference with SAD is the seasonal pattern it follows. The most commonly reported SAD symptoms include significant fatigue, pervasively sad mood, loss of interest in activities, sleeping more than usual, craving and eating more starches and sweets, gaining at least 5 percent of body weight and difficulty concentrating. Most people experience SAD symptoms to a certain extent, especially at higher latitudes. These individuals who do not meet diagnostic criteria for depression during the fall/winter months, but who experience mild to moderate symptoms during fall or winter, are considered to have a milder form of this disorder also known as subsyndromal SAD or the “winter blues.”

APA: What are the types of treatments for this condition and when should people seek treatment?

Dr. Rohan: I strongly recommend against self-diagnosis and self-treatment because depression, including SAD, is a serious mental health problem. If you struggle with the changing seasons, experience some of the symptoms mentioned above, have difficulty functioning at school or work or if your symptoms interfere with your ability to interact with your family or others during the winter months, you should talk to your doctor about a referral to a psychologist or find a psychologist yourself.

The most widely used and extensively investigated treatment for SAD is light therapy (i.e., daily exposure to bright artificial light during the symptomatic months). Light therapy devices rigorously tested in clinical trials for SAD emit a controlled amount of cool, white fluorescent or full spectrum light with a built-in screen to filter out harmful ultraviolet rays. Clinical practice guidelines for SAD recommend daily use of light therapy each year from onset of the first symptom until the time in the spring when SAD symptoms would naturally resolve on their own. Compliance and consistency with the daily regimen are very important for benefits. Light therapy devices are commercially available without a prescription. However, because of the possible side effects, such as headache, eye strain and feeling agitated, and because the dose of the light needs to be adjusted to each patient, it is best to use light therapy under the supervision of a mental health provider with expertise in light therapy. Ask your psychologist if he or she feels comfortable supervising your light therapy and side effects or if they can refer you to someone with that expertise. When light therapy fails, antidepressant medications are widely regarded as the second line of treatment for SAD. 

APA: You’re researching the best ways to treat SAD, including some work on comparing the effectiveness of cognitive-behavioral therapy with light therapy. What have you learned?

Dr. Rohan: For the past 12 years, my laboratory has been developing and testing a novel cognitive-behavioral therapy for SAD, with promising results. CBT is a type of talk therapy used and researched extensively for non-seasonal depression since the 1960s, but we are the first group to apply the treatment to SAD. We previously published a clinical trial for SAD that compared standard light therapy, CBT and the combination of CBT and light therapy to a control group on a wait list for treatment. We found that CBT, light therapy and combination treatment all improved depression more than the control group and all three of these methods showed large and comparable improvements in SAD symptoms across the six weeks of treatment in the winter. A year later, patients who had been treated solely with CBT generally had better outcomes than those who had been treated with light therapy alone. In contrast, the combined treatment group did not fare any better than the light therapy only group the next winter. These results suggest that treating someone initially with just CBT may be more effective in the long term. My lab is completing a study to find out if these results hold in a larger, more definitive study funded by the National Institutes of Mental Health. In that study, we treated 153 adults with SAD with either CBT or light therapy and we are following them for two consecutive winters to measure future symptom severity and SAD recurrences after treatment ends. I am most interested in long-term outcomes, meaning how to keep people well over time.

APA: How can cognitive-behavioral therapy be tailored for SAD? 

Dr. Rohan: The CBT for SAD treatment we have been testing includes 12 structured sessions, delivered two times per week over six weeks in the winter. The sessions focus on developing skills to improve coping with the seasons. The therapist works with the patient to foster two types of skills: behavioral (doing) skills and cognitive (thinking) skills. The behavioral skills involve identifying, scheduling and doing pleasurable, engaging activities every day in the winter. Over time, these proactive behaviors are meant to counteract the down, lethargic mood and the tendency to give in to “hibernation” urges that are so common in SAD. The cognitive skills involve learning to identify and challenge negative thoughts when experiencing SAD symptoms. In our CBT program, we encourage patients to aggressively apply the skills they learn in CBT before symptoms start, typically very early in the fall or around the end of daylight saving time, to manage their moods and prevent slipping back into old patterns that contribute to depression. This “tool box” of skills is assumed to be important for long-term benefits after formal CBT with the therapist ends.

APA: Can people be cured of this disorder?

Dr. Rohan: SAD can be effectively treated but the status of the research in the field is unfortunately not at the point where we can say we have a “cure” for SAD. The good news is that research in the field shows effective treatments are available, including light therapy, medications and CBT. So there are options for people affected by SAD. There is not a one-size-fits-all treatment approach. Different things work for different people. After finding a treatment or treatments that substantially improve acute SAD symptoms in the winter, it is important that the long-term treatment plan include specific steps to try to prevent the return of SAD, or lessen its impact in subsequent fall/winter seasons.