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Winter Depression Research Clinic


To study the pathophysiology of seasonal mood changes and to develop new more effective and efficient treatments.

What is Winter Depression?

Winter Depression or Seasonal Affective Disorder (SAD) is an illness that affects people's mood and behaviors. The symptoms of SAD usually begin to appear gradually throughout September and October and last through March or April. Research suggests that SAD may affect as many as 11 million people in the United States. Up to four times as many women suffer from SAD as men, and it tends to run in families. Geographic location also plays a role in the likelihood of the occurrence of SAD. Those who live in Canada and the northern United States are up to eight times more likely to suffer from SAD than people living in sunny areas such as Florida and Mexico.

Signs and Symptoms of Winter Depression

Like all illnesses it is associated with specific symptoms. These symptoms are largely absent in the late spring and summer months:

  • depressed mood and fatigue
  • carbohydrate cravings, especially for sweets and/or starches
  • increased appetite and/or weight gain
  • oversleeping or difficulty awakening in the morning
  • reduced work productivity
  • withdrawal from social contacts

How is SAD Treated?

Many experts believe that exposure to bright light in the morning is an effective therapy for SAD.

Experts typically recommend:

  • Treatment with a 10,000 lux light box for 30 to 45 minutes at a consistent time each morning.
  • Treatment should be done every day including weekends, and should be completed before 8 am (earlier if possible).
  • The light box should be capable of providing light with an intensity of 10,000 photopic lux at a distance of at least 12 inches.
  • The device should be of sufficient size to provide this illumination even if the patient moves somewhat during use: full size light boxes are the most convenient and have a light emitting area of at least 12 inches by 12 inches.

Treatment of depression should always be done under the supervision of a qualified mental health practitioner. Risks of light treatment include risks like any other treatment of depression, such as induction of elevated, manic, anxious, or suicidal states. Individuals with any disease of the eye or any illness that may predispose to diseases of the retina such as diabetes, individuals over 65, or individuals taking photosensitizing drugs should consult with an ophthalmologist before undertaking light treatment.

Yale Faculty

Paul Desan, MD, PhD