By Madison Avenue TMS & Psychiatry - Published on November 20, 2025

Last updated on November 20, 2025

‘Tis the season: With autumn well under way, the days are growing shorter — and once daylight saving time goes into effect, it may be dark outside when you wake up, leave work or both. That can make sunshine feel like a precious but scarce resource.

That lack of daylight can have a profound effect on many people, giving rise to a condition known as seasonal affective disorder, or SAD. It’s typically associated with the shorter daylight experienced in the late fall and winter months, though there’s a much less common form of the condition known as summer-pattern SAD, or summer depression. 

Although it’s seasonal in the sense that symptoms usually clear up with the return of more daylight in the spring, SAD is considered a form of depression, with the ability to affect your behavior, feelings and thinking. As such, you’re at increased risk of having SAD if you have a major depressive or bipolar disorder, or have blood relatives who do.

Other risk factors include living in cloudy locales or in far-northern or far-southern latitudes that receive significantly less sunlight in winter.

Symptoms of SAD

Seasonal affective disorder can mirror other types of depression in its signs and symptoms:

• Feeling sad, listless or down
• Feeling hopeless or worthless
• Low energy and sluggishness
• Loss of interest in things you usually enjoy
• Sleeping too much
• Overeating, craving carbohydrates and gaining weight 
• Difficulty focusing

The primary difference from other forms of depression is its pattern of occurring during specific seasons.

What Causes SAD?

While the causes of SAD are not entirely understood, researchers have focused on the role of serotonin, a neurotransmitter chemical in the brain that helps regulate mood. It’s believed that shorter daylight hours interfere with certain molecules that help maintain serotonin, leading to lower levels during the fall and winter.

Another contributing factor may be a deficiency of vitamin D, an important nutrient that influences serotonin production. While vitamin D can be derived from certain fatty foods and nutritional supplements, the biggest source is through exposure of the skin to sunlight, making it harder to generate during winter in northern climates like New York.

There’s also your internal biological clock, which regulates your mood, sleep and hormones, and which shifts when daylight decreases, putting you out of sync with the routines and schedules you’re accustomed to.

Lastly, research suggests a link between SAD and over-production of melatonin, a hormone that regulates sleep, making those who suffer from the disorder prone to fatigue and oversleeping. 

How Do You Treat SAD?

First off, rather than trying to diagnose yourself, you should see your doctor for help determining whether you have seasonal affective disorder or something more serious. Your doctor may refer you to a psychologist or psychiatrist, who can ask questions about your symptoms, their pattern and whether you have a family history of any mood disorders, among other things.

Once diagnosed, there are several ways to treat SAD, some of which may be combined. 

• Cognitive behavioral therapy. This form of talk therapy can help you learn ways to manage stress and cope with SAD, including by planning meaningful activities and incorporating healthy habits such as exercise, eating nutritious food and following good sleep patterns. Psychotherapy can also help you identify negative thoughts that may be making you feel worse so you can change them.
  
• Light therapy. This can range from opening the blinds at home to let in more sunlight to sitting closer to bright windows whenever indoors to purchasing a light box that uses white light to mimic sunlight. Light boxes are brighter than indoor light and have a screen to filter ultraviolet rays. They’ve been found to be effective in regulating mood and energy levels when used properly, for 15 to 30 minutes each day.
  
• Antidepressants. Your psychiatrist may prescribe a serotonin uptake inhibitor to manage your depression symptoms, possibly in combination with light therapy.
  
• Vitamin D supplements. Your therapist may recommend a supplement to help manage your symptoms.
  
• Spending more time outside. In addition to offering a break from cabin fever and providing a welcome change of scenery, getting outside exposes you to more sunlight. That said, studies suggest that it takes much longer for the body to produce sufficient vitamin D from winter sunlight in northern latitudes than in brighter, southern locales.

Get Help Treating SAD in NYC

If you’re noticing a downturn in your mood and overall outlook when the daylight diminishes, Madison Avenue TMS & Psychiatry can help. Our office in Manhattan is staffed by caring experts who listen and can tailor a treatment plan to your unique needs. 

To learn more or schedule a consultation with our team, call us at (212) 731-2033.

Madison Avenue TMS & Psychiatry