Seasonal affective disorder (SAD) impacts millions of people each winter. The farther someone lives from the equator, the greater the risk. Scientists are still learning about the causes behind SAD, and its connection to other conditions, in hopes of finding better treatments. For example, people with attention deficit hyperactivity disorder (ADHD)) are three times more likely to have symptoms of SAD than people without ADHD, according to a 2016 study published in the Journal of Psychiatric Research.
What is seasonal affective disorder (SAD)?
SAD is a type of depression that cycles with the seasons, according to the National Institutes of Health (NIH). People with SAD have symptoms that may include:
Feeling lethargic or having low energy
Sleeping more than normal
Overeating, especially carbohydrates
Withdrawing from social activities
These symptoms usually occur during the winter months, but some people do experience SAD during the summer months. The exact causes of SAD are not known, however some proposed causes include serotonin dysregulation in the brain, overproduction of melatonin, and low vitamin D levels. It is the serotonin dysregulation that might explain the association between ADHD and SAD, according to a 2006 paper published in the American Family Physician, because both disorders are characterized by an under arousal of certain brain regions and a heightened sensitivity to the physical environment.
What you can do
There are currently a few different treatments available for SAD. Light therapy, cognitive behavioral therapy, and medication all reduce symptoms. But, there haven’t been any large-scale studies to show which of these treatments is best, according to the 2006 paper published in the American Family Physician. If you experience symptoms of SAD, it is important to talk with your doctor about the different treatments to determine which one is right for you.
Light therapy — Light therapy, the most common treatment for SAD, is found to work best when it is administered in the morning, according to the 2006 paper published in the American Family Physician. Light therapy involves sitting under a bright light for 20-60 minutes per day to help make up for lost sunlight, according to the NIH. Lightboxes for SAD therapy use 10,000 lux of cool, white fluorescent light and filter out the UV rays.
Cognitive behavioral therapy (CBT) — CBT is a type of psychotherapy based on the idea that how we think (cognition), how we feel (emotion) and how we act (behavior) all interlink. To this end it works to change negative thought patterns into realistic and helpful thought patterns and behaviors. For example, CBT would coach someone to change unhelpful thoughts about staying indoors extensively into thoughts about ways to find pleasurable activities to do outdoors. According to the American Family Physician 2006 paper, a small study of 26 participants found CBT to be equally as effective as light therapy in treating SAD. There have not yet been large or long-term studies to determine the effectiveness of this treatment.
Medication — Some medications that are used to treat depression can also be used to treat SAD, according to the American Family Physician 2006 paper. For example, some studies have found that sertraline (Zoloft) and fluoxetine (Prozac) are helpful in treating people with SAD.