Seasonal Affective Disorder: Causes, Symptoms & Treatments

| Patient Education

Seasonal Affective Disorder affects millions of Americans each year. In this article, we'll explain some of the important research surrounding SAD, including steps you can take to treat the condition on your own or with the help of a medical professional at Schneck.


What is Seasonal Affective Disorder?

Seasonal Affective Disorder (SAD) is a type of recurrent depression related to the changing of seasons. If you have SAD, you may experience negative shifts in your mood or energy levels at the beginning of spring or the beginning of fall and into the winter months. SAD is a fairly common condition, affecting 1–3% of adults in temperate climates.

Man touching his head

What Causes Seasonal Affective Disorder?

Although SAD occurs during the change of seasons, scientists don't totally understand what causes it. Existing research offers a few explanations:

  • Serotonin levels. Individuals with SAD may have reduced activity of serotonin, a brain chemical that helps regulate mood. Less exposure to sunlight during the winter months can also cause a drop in serotonin levels, leading to feelings of depression.

  • Vitamin D deficiency. You probably know that sunlight provides vitamin D; it's also believed to boost serotonin levels. So, less exposure to sun could also lead to deficits in vitamin D.

  • Melatonin levels. Research suggests that individuals with SAD produce too much melatonin, a critical hormone for maintaining appropriate sleep cycles. Too much melatonin can lead to sleepiness and depression.

  • Circadian rhythm disruptions. Your circadian rhythm is like your body's internal clock, helping stabilize energy levels throughout the day.

According to the National Institute of Mental Health, for people with SAD, "changes in serotonin and melatonin levels disrupt the normal daily rhythms. As a result, they can no longer adjust to the seasonal changes in day length, leading to sleep, mood, and behavior changes."

Symptoms of Seasonal Affective Disorder

We already mentioned several SAD symptoms above. Other signs of SAD vary by season and may include the following:

Winter-onset symptomsSpring-onset symptoms

Oversleeping (hypercomnia)

Trouble sleeping (insomnia)

OvereatingDecreased appetite
Weight gainWeight loss
Social withdrawalRestlessness and anxiety
Feeling sluggish or fatiguedIrritability or anger outbreaks


Remember that SAD is a recurrent condition, meaning it comes back around at the same time(s) each year. If you've routinely experienced any of the above symptoms, you may have Seasonal Affective Disorder.

Get in touch with a mental health professional at Schneck.

Women enjoying outside weather

Who's at Risk of Seasonal Affective Disorder?

Millions of Americans experience SAD every year. Not surprisingly, research indicates that people living in northern regions are more likely to be affected. That's because those regions undergo longer, colder winters with less sunlight. Here in Seymour, Indiana, winters are relatively mild. But we don't receive nearly as much sunlight as a state like Florida.

SAD often runs in families, being more common in people with blood relatives who also have other mental conditions, such as schizophrenia bipolar disorder. Additionally, if you have personally dealt with other mental health complications, you may be at a higher risk of experiencing SAD.

You can begin treating SAD on your own simply by getting more sunlight and moving your body more. Both of these activities can be challenging during the winter months, of course, but they will help boost your mood and energy.

Mental Health Services at Schneck

If you believe you're struggling with Seasonal Affective Disorder—or if you have other concerns for your mental health—Schneck is here to help. Our Mental Health & Wellness team provides responsive, high-quality mental healthcare with the ultimate goal of restoring patients to an optimal level of health—and hope.

Our doctors can prescribe a plan to help you feel better this (or any) season. Simply contact our office to get started.

Contact Schneck Mental Health & Wellness

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