Seasonal depression is not just holiday-related doldrums. When daylight begins to grow shorter, temperatures get chillier, and the sky can be gray for days at a time, as many as 20 million Americans experience a recurring major depressive disorder known as seasonal affective disorder (SAD).
Is seasonal depression real?
According to the National Institutes of Health, this type of seasonal depression tends to increase with latitude in the US, with as many as 9.7 percent of people affected in New Hampshire and 1.4 percent in Florida. Globally, Norway has reported figures as high as 14% of its population suffering. SAD can affect everything from performance at work or school to sleep patterns, appetite, and willingness to participate in activities that normally cause pleasure when the depression is in remission. Seasonal depression is classified in the Diagnostic and Statistical Manual for Mental Disorders (DSM) as a major depressive disorder with seasonal patterns—most commonly with onset in the fall and winter, but less commonly, spring and summer.
While there is no known cause for SAD, several factors are believed to come into play:
- Your circadian rhythm, or biological clock, could be disrupted by lower levels of sunlight, leading to feelings of depression.
- Your levels of melatonin, a natural hormone that affects sleep and mood, may experience seasonal disruption, resulting in increased drowsiness.
- A drop in serotonin, a neurotransmitter, from reduced sunlight in the winter, could trigger depression.
- Some research indicates people with SAD naturally produce lower levels of vitamin D.
SAD is usually diagnosed in individuals who have experienced symptoms for three consecutive winters with symptoms abating in the spring and summer.
Understanding seasonal depression
Risk factors for SAD include a family history of depression, living far from the equator where there is less sunlight in the winter and longer days in the summer, and having been diagnosed with depression or bipolar disorder. People often confuse or conflate it with “winter blues,” also described in the DSM, but with less severe symptoms.
The key difference between holiday depression and seasonal depression is that holiday depression is stress-induced, while seasonal depression, or SAD, is a major depressive disorder. Many people feel sad during the holiday season when stresses pile up and traditions bring up past memories—but the sadness is typically short-term. Seasonal depression is a more severe disorder that lasts for months and stems from biological, neurological, and genetic factors.
People experiencing SAD can have a number of symptoms of major depression but also have important seasonal indicators. The most common symptoms include:
- Sadness and/or feelings of hopelessness
- Oversleeping or a heightened need for sleep
- Appetite changes, specifically craving carbohydrates or sweets
- Weight gain
- Fatigue and a significant lack of energy
- Lack of interest in usual activities
- A heavy or “leaden” feeling in arms or legs
- Trouble concentrating
- Social withdrawal and avoidance
If seasonal depression symptoms interfere with work or school, cause self-imposed social isolation, or lead to substance abuse, it should be taken seriously. If you or someone you love has thoughts of suicide, call 911, go to your local emergency room, or call the National Suicide Prevention Lifeline at 1-800-273-8255.
Treating seasonal depression
Medication, light therapy, and psychotherapy have all been used to treat SAD. Phototherapy, or light therapy, is often one of the first treatments for seasonal depression. It involves sitting in front of a lightbox containing fluorescent light tubes that are covered with a screen to block UV waves. It’s typically recommended that you do this within the first hour of waking, for a period of 15 to 30 minutes. You don’t have to stare at it—you can read, eat breakfast, or perform other activities during this time as long as you’re within two to three feet of the lightbox. People with bipolar disorder may not be good candidates for light therapy, and you should always consult a physician before beginning any new treatments.
Antidepressant medications, which may be used alone or in conjunction with light therapy, are often prescribed to help more severe symptoms and may take several weeks to take full effect. Cognitive-behavioral therapy, or talk therapy, has also shown promising results in treating individuals suffering from SAD. Therapy sessions can help improve stress management and identify healthy ways to cope with negative thoughts or social avoidance.
Certain lifestyle practices can also improve the symptoms of SAD, such as spending more time outdoors and increasing exposure to natural light at home and at the office. Meditation, yoga, guided imagery, and art or music therapy may also help improve symptoms. Planning physical activity and eating a well-balanced diet ahead of the fall and winter season can also boost your mood and get you into positive habits before the urge to stay in bed strikes. Starting light therapy before the onset of your symptoms may stave off more severe feelings.