Seasonal Affective Disorder (SAD)

During the fall and winter months, some people suffer from symptoms of depression that can appear gradually or come on all at once. These symptoms often dissipate as spring arrives and stay in remission through the summer months. For some people, this is a sign that they suffer from Seasonal Affective Disorder (SAD).


Symptoms usually appear during the colder months of fall and winter, when there is less exposure to sunlight during the day. Depression symptoms can be mild to moderate, but they can become severe. Those who work long hours inside office buildings with few windows may experience symptoms all year, and some individuals may note changes in mood during long stretches of cloudy weather. Symptoms can include, but are not limited to:

  •  fatigue
  • lack of interest in normal activities
  • social withdrawal
  • craving foods high in carbohydrates
  • weight gain

 Those with SAD may not experience every symptom. For example, energy level may be normal while carbohydrate craving may be extreme. Sometimes a symptom is opposite the norm, such as weight loss as opposed to weight gain.

How Does SAD Develop?

SAD has been linked to a biochemical imbalance in the brain prompted by shorter daylight hours and a lack of sunlight in winter. Just as sunlight affects the seasonal activities of animals, SAD may be an effect of this seasonal light variation in humans. As seasons change, people experience a shift in their biological internal clock or circadian rhythm that can cause them to be out of step with their daily schedule.

Melatonin, a sleep-related hormone, also has been associated with SAD. When the days are shorter and darker, more melatonin is produced. Researchers have proved that bright light makes a difference to the brain chemistry. The most difficult months for SAD sufferers seem to be January and February. SAD may begin at any age, but the main age of onset is between 18 and 30 years.


Increased exposure to sunlight can improve symptoms of SAD. This can be a long walk outside or arranging your home or office so that you are exposed to a window during the day. If your depressive symptoms are severe enough to significantly affect your daily living, making an appointment to meet with a therapist can provide additional relief, and in some cases, prescription of antidepressants.

If you feel you are suffering from SAD, it is important to seek the help of a trained medical professional. SAD can be misdiagnosed as hypothyroidism, hypoglycemia, infectious mononucleosis, and other viral infections; so proper evaluation is necessary. For some people, SAD may be confused with a more serious condition like severe depression or bipolar disorder.

A mental health professional can diagnose the symptoms and suggest therapy options. With the right course of treatment, SAD can be a manageable condition.

 Reviewed by Tzipora Spira, LMSW, Project Ohr