What is seasonal depression?

Dr. Charles J. Sophy, MD
Adolescent Medicine Specialist

Have you ever noticed how a gray, rainy day makes you feel gloomy and tired, but a sunny day can leave you feeling cheerful and energized? Well, there's a scientific reason for this. Insufficient exposure to sunlight has been associated with low levels of melatonin and serotonin, carbohydrate craving, weight gain, and sleep disturbance.

Causes of Seasonal Affective Disorder:

  • SAD is believed to be caused by a disturbance in the normal circadian rhythm of the body. Light entering through the eyes influences this rhythm. When it is dark, the pineal gland produces a substance called melatonin which is responsible for the drowsiness we feel each day after dusk. Light entering the eyes at dawn shuts off the production of melatonin. During the shorter days of winter, when people may rise before dawn or not leave their offices until after sunset, these normal rhythms may become disrupted, producing the symptoms of SAD. 
  • There is also evidence linking SAD to a reduced amount of the neurotransmitter serotonin. Serotonin is the feel-good substance that is increased by antidepressants called selective serotonin reuptake inhibitors (SSRIs). This decrease in serotonin production may be responsible for many of the symptoms of SAD, such as depression and carbohydrate cravings.
Dr. Deborah Serani, PsyD
Psychology Specialist

Seasonal Affective Disorder (SAD) is a subcategory of major depressive disorder and symptoms occur seasonally or in cycles. Symptoms include many of the same symptoms of depression: sadness, anxiety, lost interest in usual activities, withdrawal from social activities and an inability to concentrate. The difference though, is that these symptoms resolve each Spring and tend to occur again in late Fall.

There is a relationship between winter and depression. There is a known condition called seasonal affective disorder, which was first identified as "winter depression" by researchers at the National Institute of Mental Health in 1984. It correlates with the shortening of days in the late fall and early winter when less natural sunlight is available. This condition has been found to be more common in residents of the more northern latitudes like Minnesota than in the more southern latitudes like Florida.

Dr. Kimberley Taylor, PsyD
Psychology Specialist

Seasonal Affective Disorder, or SAD, is found among individuals who are sensitive to the changes in seasons and more specifically to the amount of sunlight during the day.  They usually have normal mental health during the rest of the year and only become depresed during certain periods of the year.

There are many different treatments for seasonal affective disorder, including light therapy with sunlight or specialty lights, antidepressant medication, cognitive-behavioral therapy, ionized-air administration, and supplementation of melatonin.

Dr. Sudeepta Varma, MD
Psychiatrist (Therapist)

Many people feel blue as the winter months approach. It starts to get darker much earlier, there is overall less sunlight, we tend to stay indoors, are less physically active and the weather is much colder. All of this can contribute to people feeling a little blue.

However, seasonal depression is different and more than just the “winter blues”. In seasonal depression we see that people who are not normally depressed the rest of the year, meet criteria for a major depressive disorder—only in the winter, year after year, and it’s not related to any seasonal stressors. Symptoms include typical features of depression such as low mood, concentration and memory problems, feelings of guilt, hopelessness, helplessness, sleep disturbances, appetite changes, and in severe cases, even thoughts or plans of suicide. In addition to the typical symptoms of depression, we see that people will feel more fatigued and crave carbohydrate-rich foods.

Seasonal affective disorder, or SAD, is a mood disorder characterized by depression related to a certain season of the year, especially winter. However, SAD is often not described as a separate mood disorder but as a "specifier," referring to the seasonal pattern of major depressive episodes that can occur within major depression and manic depression.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.