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Diseases & Conditions A - Z
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Seasonal Affective Disorder

What Is Seasonal Affective Disorder?

Seasonal affective disorder (SAD) is a form of depression. People affected by SAD display symptoms of depression at the same time every year, typically during the fall and winter months.

According to the American Academy of Family Physicians (AAFP), seasonal affective disorder is more likely to affect women than men, and children and adolescents are seldom diagnosed with it (AAFP).

SAD is also known as winter-onset depression. Summer-onset depression can be a type of SAD, but it is rare.

Causes of Seasonal Affective Disorder

SAD may be caused by changes in your body’s chemical balance and internal clock.

Within your body are two chemicals—melatonin and serotonin—that help to keep your mood balanced and your sleep patterns intact. During the colder months, your levels of melatonin and serotonin may change.

This decrease can throw off your circadian rhythm, or your body’s internal clock that helps you to know when you should sleep and when you should wake up. When your circadian rhythm is disrupted, you cannot sleep well.

These changes can de-stabilize your mood, and may lead to depression.

Risk Factors for Seasonal Affective Disorder

Certain population groups are more likely than others to suffer from seasonal affective disorder. Although women have a higher risk of developing SAD, men with the condition often display more severe symptoms (Mayo Clinic).

People who suffer from certain forms of mental illness, such as bipolar disorder, are more likely to also suffer from SAD. A family history of depression can be another contributing factor to this condition.

People who live in cold climates have an increased chance of developing seasonal affective disorder. This is most likely due to the decrease in sunlight hours during the winter.

Seasonal Affective Disorder Symptoms

The symptoms of seasonal affective disorder vary from person to person, and according to the type of SAD. Winter-onset depression is characterized by:

  • change in appetite
  • restlessness and irritability
  • generalized anxiety
  • loss of energy
  • headaches
  • loss of interest in hobbies and activities
  • sleeping longer hours
  • weight gain
  • feelings of hopelessness and guilt

People who suffer from summer-onset SAD may experience some of the same symptoms as winter-onset depression. However, additional or different symptoms are common, such as:

  • increased libido
  • weight loss
  • insomnia
  • loss of appetite

Diagnosing Seasonal Affective Disorder

Your doctor will perform a physical exam and ask you questions about your emotional health to determine if you have SAD. You should answer with as many details as you can about your mental state, your relationships, professional life, eating patterns, and sleep schedule. How you feel about all of these parts of your life can help your doctor make a firm diagnosis.

Your doctor might also administer a test called the Seasonal Pattern Assessment Questionnaire (SPAQ). This is a series of questions about your daily activities, diet, and mood. The SPAQ is a widely used diagnostic tool, but its reliability varies among users (Lurie, et al., 2006).

You need to meet certain criteria established in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM) to be diagnosed with SAD:

  1. You show symptoms of depression at the same time of year for at least two consecutive years.
  2. Your depression lifts at the end of the season.
  3. No other reasons for your depression exist.
  4. Medical testing is another component in diagnosing seasonal affective depression. Your doctor may run blood tests to measure hormone levels. This will determine if there is an underlying condition that might be causing your symptoms.

Treatment for Seasonal Affective Disorder

Light therapy is the primary treatment for SAD. A portable light box provides you with a bright light that mimics sunlight. Light therapy, also called phototherapy, is a daily treatment that you will undergo throughout the winter season.

Generally, a 30-minute light session each day is enough for your brain to produce chemicals to lift your mood. According to the Mayo Clinic, results can be seen in as little as two to four days (Mayo Clinic).

You should remember that sitting outside in the sun or going to a tanning salon does not offer the same results as the specialized light box. You will sit several feet away from the box, and the light does not damage your skin.

For some people, phototherapy may not be enough to treat their winter-onset depression. It also may not be effective at all for summer-onset depression. In these cases, antidepressant medications may give you some relief. Prozac, Zoloft, and Paxil are commonly prescribed medications used to treat seasonal affective disorder.

Psychotherapy may be another way to manage your seasonal affective depression. Although talking with a therapist cannot change your body’s chemical reactions, it might help you to change your behavior and give you healthy coping mechanisms for your symptoms. Discussing your feelings with a qualified counselor may help you turn negative emotions into positive thoughts.

You can also help yourself feel better by being proactive. Exercising, following a balanced diet, and exposing yourself to natural light may lift your mood. Keep your window shades open and take a daily walk to relieve your anxiety.

Outlook for Seasonal Affective Disorder

Light therapy, medication, and behavior modification are able to help most people with their seasonal affective disorder. You should notify your healthcare provider immediately if you or a loved one with SAD begins to exhibit suicidal thoughts or actions.

Content licensed from:

Written by: Erica Roth
Medically reviewed : George Krucik, MD

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.
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