Seasonal Affective Disorder (SAD)

Symptoms | Causes | Diagnostic Criteria | Treatments

Seasonal affective disorder is a type of depression that comes and goes as the seasons change. People who live in countries such as Norway, Russia, and Greenland may have a higher risk of experiencing the symptoms of this disorder due to the long periods of cold, gloomy weather.

In fact, seasonal affective disorder is not recognized as a mental illness upon itself, but is instead noted as a subset of major depression, according to the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).


Although someone with seasonal affective disorder will likely experience depressive symptoms during the months of fall and winter, it is also possible for them to experience these symptoms in the months of spring and summer also, although it is less common. However, in some parts of the northern world, much of their weather throughout the year is likely to be dreary and cold.

Symptoms of Seasonal Affective Disorder

Someone suffering from seasonal affective disorder will experience most of the symptoms of major depressive disorder. This will entail experiencing a great deal of sadness and emptiness even when there is no apparent reason to feel that way. Unlike typical depression, someone’s symptoms of seasonal affective disorder will occur due to the type of weather in their environment.

Their mood will remain depressive, but the severity of their symptoms will likely vary depending on the dreariness of the weather. For instance, someone with severe seasonal affective disorder may experience the worst of their symptoms in the dark months of winter, but feel much less severe symptoms during the months of summer, depending on what part of the world they live in.

Someone with this condition can also expect to experience a lack of interest in things once enjoyed. The gloomy weather that surrounds them may sap their energy and creativity. Below, you will see some more symptoms of seasonal affective disorder:

  • Deep sadness
  • Lack of energy
  • Loss of interest in things once loved
  • Hopelessness
  • Apathetic toward most things
  • Suicidal ideation
  • Loss of appetite
  • Lack of motivation

Causes of Seasonal Affective Disorder

Temperamental, environmental, genetic, and physiological factors are all likely to play key roles in the development of this mental illness. Individuals with a family history of depression may be at a higher risk for developing it themselves.

Gloomy or dreary weather is one of the main causes of seasonal affective disorder. People who live very far from the equator (e.g. Canada, Iceland, Russia, Alaska, etc.) will likely have a much higher risk for developing this condition than if they lived in Brazil or Mexico, for example. This has to do with amount of visible sunlight people in these locations are subjected to.

Besides environmental factors such as this, genetics are also likely to play very significant roles in the development of this condition. For instance, if someone has a family history of mental illness, especially of mood disorders, then they may also have a higher chance of developing seasonal affective disorder. This will likely be due to them also having a higher chance of having the genetic makeup that will allow for such a disorder to develop in the first place.

Although we do not definitively know what causes all mood disorders, there is an overwhelming consensus among mental health professionals that this condition is caused by constant gloomy weather, genetics, temperament, brain chemistry, and other environmental factors.


Diagnostic Criteria

According to the DSM-5, the diagnostic criteria for seasonal affective disorder are as follows:

  1. There has been a regular temporal relationship between the onset of major depressive episodes in major depressive disorder and a particular time of the year (e.g., in the fall or winter). Note: Do not include cases in which there is an obvious effect of seasonally related psychosocial stressors (e.g., regularly being unemployed every winter).
  2. Full remissions (or change from major depression to mania or hypomania) also occur at a characteristic time of the year (e.g., depression disappears in the spring).
  3. In the last 2 years, two major depressive episodes have occurred that demonstrate the temporal seasonal relationships defined above and no non-seasonal major depressive episodes have occurred during that same period.
  4. Seasonal major depressive episodes (as described above) substantially outnumber the non-seasonal major depressive episodes that may have occurred over the individual’s lifetime.

Treatments for Seasonal Affective Disorder

There are several different treatments for seasonal depression. These include light therapy, talk therapy, and psychiatric medication. Mood disorders such as seasonal affective disorder are very treatable, especially if a healthy diet and consistent exercise are embraced.

Light therapy can be implemented by having the patient spend more time outside in the sunlight. They can also use a computer-controlled heliostat to reflect sunlight into the windows of a home or office. They may also be prescribed to use what are called light therapy lamps. Light therapy lamps are used to help uplift the mood of the person suffering with seasonal affective disorder as it is a lack of sunlight exposure that is a major cause of this disorder in the first place.

Talk therapy like cognitive behavioral therapy (CBT) may be able to help someone suffering from this condition as it is also a very common form of treatment for people suffering from major depressive disorder. CBT may be able to help the depressed person with discovering and implementing new, healthier behaviors when they feel down.

Antidepressants such as Zoloft (Sertraline) may be very beneficial for someone suffering from seasonal affective disorder as well. However, this is something you should first discuss with your doctor.

If you think you may be suffering from some of the symptoms of this condition, then you may benefit from therapy. Feel free to reach out to your doctor or local mental health clinic to see what your available options are and to see if there is any sort of discount or promo code available to help you with the costs of treatment, as well as if your health insurance will cover treatment costs.


  • Diagnostic and Statistical Manual of Mental Disorders (DSM-5)

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