What Are the Causes of Seasonal Affective Disorder (SAD) and How Do You Fight It?

Medically Reviewed on 12/13/2021

Symptoms of seasonal affective disorder

Seasonal affective disorder is a type of depression linked to the seasons. You fight seasonal affective disorder by using light therapy, talk therapy and medication.
Seasonal affective disorder is a type of depression linked to the seasons. You fight seasonal affective disorder by using light therapy, talk therapy and medication.

Seasonal affective disorder is a type of depression linked to the seasons. It's most common during fall and winter. People with seasonal affective disorder experience mood changes and other symptoms of depression like fatigue and loss of interest in normal activities. The condition fades when the weather changes again. 

Seasonal affective disorder can be treated. A combination of light therapy, medication, and counseling may be helpful. Learning how seasons affect your mood will help you prepare for mood changes before they become a problem. 

Seasonal affective disorder has many of the same symptoms as typical depression, including: 

  • Feeling sad or having a depressed mood
  • Loss of interest in activities you usually enjoy
  • Changes in appetite
  • Sleeping more than usual or a change in sleep patterns
  • Fatigue and decreased energy
  • Restlessness
  • Feeling worthless or guilty
  • Trouble thinking clearly, concentrating, or making decisions

Seasonal affective disorder is very common. It usually begins in adulthood, and it affects women more often than men. People in northern regions are more likely to have the condition due to shorter daylight hours in winter where they live.

In severe cases, people develop thoughts of death or suicidal feelings. If you or someone you know is talking about suicide or wanting to die, get immediate medical help. You can call the national suicide prevention line at National Suicide Prevention Lifeline or 800-273-TALK (8255).

Causes of seasonal affective disorder

Experts believe that seasonal affective disorder is related to chemical changes in the brain in winter. Research shows that people produce less of the chemical serotonin when there are fewer hours of sunlight. Serotonin is a mood-regulating neurotransmitter, and too little of it often causes depression.

The increased number of dark hours also leads to higher levels of melatonin in the brain. Melatonin is responsible for making you feel sleepy. The increase of melatonin can lead to fatigue and trouble concentrating.

Staying indoors due to winter weather can mean you're not getting enough vitamin D. You typically get vitamin D from sun exposure. Vitamin D can stimulate serotonin production, so lacking the vitamin can increase serotonin-related depression symptoms.

Some experts think that depression in winter is exacerbated by isolation and reduced access to enjoyable activities. If you're already feeling depressed due to chemical changes, the cold, darkness, and lack of social opportunities of winter can make you feel worse. You might feel cut off from friends, family, and warm-weather activities, which increases loneliness and sadness.

Treatment for seasonal affective disorder

Seasonal affective disorder is treatable. Doctors recommend a combination of counseling, antidepressant medication, and light therapy. 

Light therapy

Since lack of daylight is one of the triggers of seasonal affective disorder, light therapy that uses artificial sunlight can help reduce symptoms. You can buy a special lamp that emits UV light and mimics sunlight. The wavelengths won't increase your risk of skin cancer or sunburn, so you can use it without worrying about skin health.

Researchers have found that using the light for 20-30 minutes per day can improve mood within 2-3 weeks. You should continue using the light daily to avoid having a relapse of depressive symptoms. People who benefit from light therapy often begin using it during the fall to prevent symptoms from starting as the days get shorter.

Exposure to natural sunlight can be beneficial as well. When weather permits, you can spend time outdoors to get the benefit of the sun on your skin. Spending time in areas of your home or office with windows that get plenty of sunlight may also be helpful.

Talk therapy

Therapy with a mental health professional is a well-respected treatment for any type of depression. A psychologist or psychiatrist can help you manage your emotions during episodes of depression. Research shows that cognitive behavior therapy is very helpful for people who need treatment for depression.


Antidepressant medications are often highly effective at controlling symptoms of seasonal affective disorder. Selective serotonin reuptake inhibitors (SSRIs) control serotonin levels in your brain. This can offset the effects of decreased serotonin due to seasonal changes. 

You may need to take antidepressants for several weeks before you start to feel the effects. You will need to keep taking the medication as directed to avoid a recurrence of depression. You might also experience unpleasant side effects from skipping doses. Your doctor will help you manage your medication over time.

You may be able to discontinue treatment once the season changes and your symptoms become less bothersome. You may find that symptoms return in a recognizable pattern each year. You and your doctor can plan ahead to prevent serious depressive feelings by starting treatment before seasonal changes. 

If you think you have seasonal affective disorder, or any type of depression, talk to your doctor. They can help you get the support you need to feel better. Insurance plans are required to cover mental health services, including medication for mental health conditions.

Health Solutions From Our Sponsors

Medically Reviewed on 12/13/2021

American Psychiatric Organization: "Seasonal Affective Disorder (SAD)."

HealthCare.gov: "Mental health & substance abuse coverage."

National Health Service: "Overview - Antidepressants."

National Institute of Mental Health: "Seasonal Affective Disorder."

National Suicide Prevention Lifeline: "Talk To Someone Now."