Why Seasonal Affective Disorder Literally Makes You SAD

SAD is an acronym for Seasonal Affective Disorder, which is a cause of depression for many in the winter months

Why Seasonal Affective Disorder Makes People Sad

Seasonal Affective Disorder (SAD) is a recurrent type of clinical depression that affects about 5% of the population according the American Psychiatric Association, mostly in the winter months when the days are shorter, and mostly among women (about four times as much, actually). Symptoms include:

  • Low energy
  • Loss of interest in activities
  • Poor concentration
  • Sadness
  • Changes in sleep and appetite
  • Irritability
  • Decreased sex drive
  • Feelings of worthlessness

People with SAD tend to be tired all the time, and some report craving carbohydrates and weight gain. Treatments include light therapy, anti-depressants, Vitamin D, and counseling.

SAD Explained

But what is really happening with our minds and bodies to cause all of these symptoms? The cause seems to stem from two hormones - serotonin and melatonin. People with SAD have trouble regulating the neurotransmitter serotonin—which is responsible for balancing mood. People have a protein that assists with serotonin transport called SERT. When SERT is high, that means serotonin activity is low—leading to depression. Sunlight typically keeps SERT low, but as sunlight decreases, a decrease in serotonin activity also occurs. Based on a Johns Hopkins article describing SAD, people with this disorder also overproduce melatonin, which most people know is used to help sleep. Thus, people with SAD feel lethargic and sleepy. Decreased Serotonin and increased Melatonin impact circadian rhythms. Additionally, Vitamin D is often deficient—and low Vitamin D is associated with clinically depressive Symptoms.

Treatment Options

light therapy products can help fight the effects of SAD (seasonal affective disorder)We mentioned a few treatment options like anti-depressants, vitamin D and counseling. But one of the most commonly used treatments is called Light Therapy, or Bright Light Therapy. These products, which you can find online, emit full spectrum light similar to sunlight-but without UV rays. Whichever one you select should provide exposure of 10,000 lux of light. This makes these light boxes approximately 20 times stronger than indoor lighting. Light therapy is typically used first thing in the morning for anywhere from 20 to 60 minutes. The Mayo Clinic has a wonderful light therapy product buying guide.


Be sure to follow the manufacture’s guidelines when using. People should not use light therapy if they have retinal disease such as macular degeneration. It is also not recommended for those on certain medications, such as Lithium, Acutane, Melatonin, and certain anti-biotics. Light therapy is not recommended for those with BiPolar Disorder unless recommended by a professional. Light therapy should be monitored by a health professional. Taking Vitamin D can also help SAD. Low Vitamin D is associated with depression due to insufficient dietary intake or little outdoor exposure to sunshine.

Other Options

The Johns Hopkins research also indicates that you can mitigate SAD symptoms by doing the following:

  • Set attainable goals, consider breaking down tasks and make reasonable priorities. Feeling better will take time, so set that expectation with yourself
  • Accept help and support from friends and family
  • Get regular exercise and eat healthy, well-balanced meals
  • Avoid alcohol and drugs since these can make depression worse

Final Thoughts, From Dr. Pam Wright

Clients often ask me how to know the difference between major depressive disorder and SAD. I tell them to think of SAD as a recurrent depression. So if you typically have depressive symptoms at the same time each year (starting during the winter months), you most likely have SAD. I highly recommend light therapy for those with SAD. I use a light myself during the winter months. It’s best to use the light first thing in the morning for 20 to 60 minutes. This helps to reduce melatonin and increase serotonin.

Dr. Pam Wright is a licensed psychologist and mental health expert. She is the founder and owner of The Life Change Group in Peachtree City, Ga.Dr. Pam Wright is a licensed psychologist and a mental health expert. She is the Founder and Director of The Life Change Group in Peachtree City, Ga. Her psychology practice is a team of therapists, counselors and psychologists offering a wide range of psychological testing and individual, couples and family counseling. Dr. Wright is also a co-host of the "Middle Age(ish)" podcast and has appeared on NBC in Atlanta.