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Seasonal Affective Disorder: What Is It?

By J. Lynn Holsman, PRS

Health & Recovery Content Specialist

Edited for Medical Content by Dr. Pennington, NP

Seasonal Affective Disorder

Seasonal Affective Disorder or SAD is estimated to affect 10 million Americans, according to Boston University. What exactly is it, and how can you protect yourself during the winter months? We will look at Seasonal Affective Disorder and some of the most common, effective treatments for it.

What is it?

SAD is a type of depression associated with the changing of the seasons. It is not uncommon for mood shifts to happen during changing seasons, but SAD brings about mood changes great enough that impact your life. It needs to be a reoccurring event for a diagnosis to be given. So for example, for the past three years, you have noticed that your mood seems to worsen right around late Fall. Depression symptoms start creeping in and you notice yourself just not enjoying things the way you used to. Maybe you’re isolating more. You would be a potential candidate for a Seasonal Affective Disorder diagnosis.


Because SAD is a part of the Depressive Disorder family, let’s look at some basic depression symptoms to fully understand Seasonal Affective Disorder. According to, these are some common symptoms of Depression:

  • Feeling sad or having a depressed mood

  • Loss of interest or pleasure in activities once enjoyed

  • Changes in appetite — weight loss or gain unrelated to dieting

  • Trouble sleeping or sleeping too much

  • Loss of energy or increased fatigue

  • Increase in purposeless physical activity (e.g., inability to sit still, pacing, handwringing) or slowed movements or speech (these actions must be severe enough to be observable by others)

  • Feeling worthless or guilty

  • Difficulty thinking, concentrating, or making decisions

  • Thoughts of death or suicide

Keep in mind that Depression can occur at any time. And there is a distinct difference between feeling sad and feeling depressed. Depression feels more like a heavy sadness that never seems to go away and drains you of your energy and joy. Now that we know what Depression looks like, let’s look at the specifics that make the symptoms Seasonal Affective Disorder.

With SAD, your symptoms begin at about the same time every year, usually with the middle to late-Fall or early Winter. Typically, symptoms with SAD begin to make their appearance when the days start getting shorter and there is less natural sunlight. To be diagnosed, the depression symptoms need to resolve with the beginning of Spring, when days start getting longer and there is more sunlight.


The first line of defense against Seasonal Affective Disorder is light therapy. There are special SAD lights that mimic the sun, and patients can sit in front of the light for any amount of time, usually at least 30 minutes per day. The length and strength of your light should come from a recommendation from your clinician. As a second resort, antidepressants can sometimes be used. But most mental health professionals agree that light therapy should always be tried first. Therapy is another tool that individuals can use to combat their Seasonal Affective Disorder. Cognitive Behavioral Therapy or CBT is a common form of therapy used for SAD. It is the same type of therapy that most clinicians use to treat Major Depressive Disorder, which is in the same category of mood disorders.


The “winter blues” is not just a saying. Some people really do struggle with their mood when the sun starts setting earlier and earlier. And the good news is that Seasonal Affective Disorder is a widely known disorder. You don’t have to suffer in silence. If you feel like you are not quite yourself, speak to your healthcare provider and let them know what is going on. There are treatments available, and you are not alone.

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