What is Seasonal Affective Disorder, Seasonal Depression?

Seasonal depression disorder, seasonal affective disorder, can cause yearly major depressive episodes. Learn more at

Seasonal depression is a type of depression that occurs at the same time every year. Seasonal depression disorder, also known as seasonal affective disorder (SAD), can be serious and crippling each year. In that way, it is different than the milder "winter blues." Most commonly, seasonal depression is in the winter in North America, as that is when there are fewer hours of sunlight.

There is no known cause of seasonal affective disorder but researchers currently think it may be related to:

  • Changes in biological clock as the seasons change
  • A disruption in the hormone melatonin
  • A drop in the neurotransmitter serotonin, possibly due to reduced sunlight

Seasonal Depression Symptoms

Seasonal depression can be related to the summer or winter months, each with their own seasonal depression symptoms. Fall and winter seasonal affective disorder symptoms include:1

  • Depression, hopelessness
  • Anxiety
  • Loss of energy
  • Social withdrawal
  • Oversleeping
  • Loss of interest in once-pleasurable activities
  • Overeating, weight gain
  • Difficulty thinking and concentrating

Seasonal depression in the summer is somewhat different. Rather than experiencing the marked low mood of depression, more irritable characteristics may come out. Typical spring and summer seasonal depression symptoms include:

  • Anxiety
  • Trouble sleeping
  • Irritability, agitation
  • Lack of appetite, weight loss
  • Increased sex drive

Seasonal Depression Treatment

While some people think they have to "tough out" seasonal depression, there is no need for this as there are effective seasonal depression treatments available. Treatments for seasonal affective disorder include psychotherapy, antidepressant medication and SAD bright light therapy.

While seasonal depression is thought to be related to biological factors, psychotherapy is still a treatment option. Therapy for seasonal depression disorder can both teach the patient about their illness as well as support the patient through depressive episodes. Psychotherapy can also treat any underlying condition that may be contributing to the seasonal depression.

Medications are also used in seasonal depression treatment, particularly if the symptoms are severe. Medications typically used in seasonal depression treatment include:

Bright light therapy is the most common seasonal depression disorder treatment. Bright light therapy attempts to increase the amount of "sunlight" received via a specialized light box. Patients spend a set period of time per day in front of their light box to treat seasonal depression. The way in which bright light therapy works, however, is unclear.

article references

APA Reference
Tracy, N. (2022, January 3). What is Seasonal Affective Disorder, Seasonal Depression?, HealthyPlace. Retrieved on 2024, July 13 from

Last Updated: January 9, 2022

Medically reviewed by Harry Croft, MD

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