Seasonal Affective Disorder (SAD) Diagnosis & Treatment

If you feel depressed, moody, or sluggish only during certain times of the year, you could have seasonal affective disorder, or SAD. It’s a type of mood disorder that triggers symptoms of depression or bipolar disorder, most often in the fall and winter when there’s less sunlight. That’s why it’s sometimes called winter depression. More rarely, you can have it in the summer.

It sometimes might take a while to diagnose SAD because it can mimic other conditions, like chronic fatigue syndrome, underactive thyroid, low blood sugar, viral illnesses, or different forms of depression or bipolar disorder.


The main feature of SAD is that your mood and behavior shift along with the calendar. It’s not a separate mood disorder, but a type of major depression or bipolar disorder, sometimes called manic depression.

You may have SAD if for the past 2 years you:

  • Had depression or mania that starts as well as ends during a specific season
  • You didn’t feel these symptoms during your “normal” seasons
  • Over your lifetime, you’ve had more seasons with than without depression or mania


Your symptoms usually will get better on their own when a new season arrives, often in the spring or summer. But treatments can make you feel better sooner, and some can help keep your condition from coming back.

You can get these therapies alone, or combine them with other treatments:

Light Therapy

Also called phototherapy, it generally works well for SAD. You sit in front of a special box or lamp that gives out up to 10,000 lux of fluorescent light -- more than 20 times brighter than most indoor light.

Researchers think the light helps your brain make more serotonin, a hormone that affects your mood.

You’ll sit 12-18 inches in front of the light for 30 minutes or more a day. The light must enter your pupils for it to work, but you do not need to stare at it directly.

You’ll usually feel better after 1-2 weeks. Phototherapy can cause headaches, blurry vision, and nausea. But side effects tend to be mild and don’t last long. The FDA hasn’t approved this treatment. Ask your doctor if phototherapy might help you. And be sure to let them know if you have glaucoma, cataracts, or other eye conditions.



Antidepressants known as selective serotonin reuptake inhibitors (SSRIs) are often the drug of choice for SAD. SSRIs are the most often prescribed type of depression drugs. Examples include:

The FDA also has approved a separate class of antidepressants called bupropion (Aplenzin, Wellbutrin XL) to treat SAD. It can be a good option if you are sensitive to the side effects of SSRIs, which can include weight gain and loss of sex drive.

Your doctor might tell you to take your meds before your symptoms start. It could take several weeks before you feel the full effects of the drugs.

Talk Therapy

If light therapy and antidepressants don’t relieve your symptoms, your doctor may suggest adding psychotherapy. A common type is cognitive behavioral therapy, but it may be hard to find a therapist who specializes in SAD.

Talk therapy can help you:

  • Learn behavior skills, such as doing something pleasurable every day in the winter
  • Notice and change negative thoughts
  • Manage stress

Vitamin D

Some people with SAD may have low blood levels of vitamin D, which comes from sunlight. But research has been mixed on whether vitamin D supplements help ease symptoms. Because of that, supplements by themselves aren’t considered useful therapy.

What You Can Do

It’s important to get treatment for all types of depression, including SAD. Along with that, you can make small changes in your life to help lessen the symptoms.

Get more sun: Get outside when the sun is shining. Open your blinds and sit by a sunny window. Too much UV light can raise your chances for skin cancer, so talk to your doctor about the risks and benefits of sun exposure.

Stay active: Exercise can help boost your mood and relieve stress and anxiety. Aim for at least 30 minutes of physical activity, 3 times a week.

Get to a brighter place: If you can, plan a trip to a sunny location. This can improve your mood and allow for more time in the sun.

Sleep the right amount of time: Try to get no more than 7-9 hours of shut-eye each night, so you can spend more hours awake.

WebMD Medical Reference Reviewed by Smitha Bhandari, MD on September 05, 2019



UpToDate: “Seasonal affective disorder: Epidemiology, clinical features, assessment, and diagnosis.”

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Cornell College: “Seasonal Affective Disorder (SAD).”

American Family Physician: “Seasonal Affective Disorder.”

Mayo Clinic: “Seasonal Affective Disorder: Tests and Diagnosis,” “Treatments and Drugs,” “Lifestyle and Home Remedies,” “Understanding a Light Box.”

National Institute of Mental Health: “Seasonal Affective Disorder.”

ULifeline: “The Dangers of Depression.”

National Health Service (UK): “Seasonal affective disorder (SAD) -- Treatment.”

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