seasonal affective disorder


Seasonal Affective Disorder – What is SAD?

Seasonal affective disorder (SAD) is a specific type of depression that emerges during a particular time of the year and fully remits with the change of seasons. This form of depression is also known under the names ‘winter blues’ or winter depression. For most people, SAD symptoms begin in the early fall and continue increasingly throughout the winter. However, some people may experience seasonal affective disorder symptoms during the spring and summer months. Seasonal depression is most common in people living in Scandinavian countries in Europe, as well as residents of Canada and northern parts of the US.

In the DSM 5 (Diagnostic and Statistical Manual of Mental Disorders) seasonal affective disorder is classified as a seasonal pattern for regular major depressive disorder that occurs during a specific time of the year and fully goes into remission otherwise.

The main characteristic of this type of depression disorder is its relation to the change of seasons. A person with seasonal affective disorder experiences the symptoms always around the same time of the year.

SAD and Major Depressive Disorder

Sometimes SAD gets confused with major depression. Seasonal affective disorder is not a milder version of major depressive disorder. SAD is a specific type of major depression that occurs seasonally. However, most people with seasonal affective disorder suffer from major depression as well.

SAD and Bipolar Affective Disorder

About 20% of people who experience SAD usually have bipolar disorder too. SAD is not the same as bipolar disorder, though. In bipolar disorder stages of depression and mania consecutively change. Still, people who have bipolar disorder may experience depression during the winter season. Similarly, during the spring/summertime a phase of mania may occur.

It is important, however, to make a distinction between SAD and bipolar disorder diagnoses, because there are significant differences in the therapeutic approach. Notify your health provider if you are seeking help for SAD if you have received a bipolar diagnosis as well.

SAD Symptoms

How to recognize the signs of seasonal affective disorder? Not every mood swing during bad weather mean SAD. If you feel moody or down from time to time, it doesn’t necessarily mean you are a candidate for SAD diagnosis. Changes in nature during fall and winter influence a great number of people. Many of us tend to feel sleepier, less energetic, and more melancholic with shorter days and scarce sunlight throughout the fall and winter months. This still doesn’t mean we suffer from seasonal affective disorder. What qualifies a person for SAD diagnosis then? Firstly, the change in mood needs to be repetitive, that is, to happen seasonally over at least two years.


Furthermore, there is an array of typical symptoms for SAD. Winter and summer seasonal affective disorder signs are slightly different. Some of the most common symptoms of fall/winter seasonal affective disorder include:

  • Low energy and feelings of exhaustion
  • Hypersensitivity and irritability
  • Feeling of heaviness in the limbs
  • Changes in appetite (carbohydrates’ rich food craving or sugar)
  • Weight gain
  • Hypersomnia (oversleeping)

On the other hand, if you experience spring/summer SAD you may have some of the following symptoms:

  • Insomnia (trouble getting to sleep)
  • Poor appetite
  • Weight loss
  • Irritability and agitation
  • Hypersensitivity
  • Anxiety

Again, these symptoms need to be repeating seasonally for a longer period of time in order for a person to be diagnosed with SAD.

Causes of Seasonal Affective Disorder

The exact cause of seasonal affective disorder remains unidentified. However, some factors that are believed to have an impact on SAD include:

  • Sunlight deficiency – shortage of light during winter months may cause feelings of hopelessness, drowsiness, low energy and discomfort. If you are experiencing SAD, your body may have problems with its ability to respond to light. Therefore people with SAD often have issues with hypersomnia (excessive sleeping).
  • Circadian rhythm, or our biological clock, is affected by the declining sunlight during the fall and winter months, which may trigger depression.
  • Melatonin and Serotonin level drop – a lack of sunlight can cause a drop in the brain neurotransmitters known as ‘happiness hormones’. Consequently, this can lead to a change in mood and sleep patterns.

Treatment of Seasonal Affective Disorder

SAD treatment may include phototherapy (light therapy), medication and psychotherapy.

Light Therapy

In phototherapy a person gets exposed to bright light by sitting a few feet from a special light therapy box. Light therapy imitates natural outdoor light and apparently provokes a change in serotonin and melatonin levels.


In some cases, SAD is effectively treated by antidepressants. It has been found that people with severe SAD symptoms respond well to this type of treatment.


People suffering from SAD may benefit from psychotherapy. Cognitive behavioural therapy has been shown to get good results. This form of treatment helps people learn how to manage their SAD symptoms and identify and change the negative thoughts that usually trigger depression.

Lifestyle Change

Some changes in lifestyle may be helpful in coping with SAD as well. Taking winter vacations and traveling to sunny destinations may help if you are suffering from the winter form of SAD.

Furthermore, try to engage in some sort of physical activity daily and spend as much time as possible outdoors. Go hiking, skiing or for a long walks.

Spend time with family and friends. Sometimes, they are the strongest support system. Although it is hard to socialize when you are feeling downheartened, make an effort to meet people.

SAD Prevention

The important thing is to manage your symptoms and prevent their progression over time. So sticking to specific treatments, as prescribed by your health-care practitioner, is important. The aforementioned lifestyle changes can also help in the prevention of seasonal affective disorder.


Further reading:

Wikipedia on SAD