Seasonal Affective Disorder (SAD)

What is seasonal affective disorder?

SAD is depression that affects some people during the winter. People who have SAD begin to feel depressed in the late fall and then feel much better as spring arrives. In the northern hemisphere, January and February are usually the months with the greatest symptoms.

How does it occur?

Seasonal affective disorder (SAD) usually comes on gradually during fall each year. It seems to lift much faster in the spring than it begins in the fall. More people experience SAD the further north they live. In the northern United States up to 25% of people report some features of SAD. Only 2 or 3% of people are severe enough to need treatment. Women are more likely to develop SAD. It usually begins during the young adult years and continues throughout life.

What causes SAD is unclear. There are several theories about hormone and brain patterns and the amount of sunlight received through the eyes and skin. To date, none of the theories fully explains SAD. We do know that exposure to light is linked to certain natural rhythms in the body. These are called circadian rhythms. These rhythms regulate body changes such as changes in mood.

What are the symptoms?

The symptoms of SAD are more specific and somewhat different from other depressions. If you have SAD, in the fall you are likely to:

• feel uninterested in doing usually fun things
• have an increased appetite with a craving for foods with starch (like potatoes and bread)
• gain weight
• have trouble getting up in the morning and often want an afternoon nap
• feel tired and slowed down much of the time
• have lower sexual desire and function
• have trouble concentrating
• have worse than usual premenstrual symptoms if you are a woman

When spring arrives each year, you are likely to feel a "high" and have a rush of energy. For a few people, the springtime "high" borders on mania. These symptoms must be a pattern for at least 2 years before they are considered seasonal affective disorder.

How is it diagnosed?

Your healthcare provider or a mental health professional can tell you if your symptoms are related to seasonal affective disorder. He or she will ask about your symptoms, history and any drug or alcohol use. You may be asked to have some lab tests to rule out medical problems such as hormone imbalances. There are no lab tests to diagnose seasonal affective disorder.

How is it treated?

The most effective treatment for SAD is increasing exposure to sunlight or artificial light that is like sunlight. Treatment for depression, such as medicine and psychotherapy, are also helpful.

Light Therapy

Special fluorescent light bulbs that imitate sunlight are used. These are up to 25 times as bright as normal fluorescent bulbs. Such bulbs range in the amount of light (measured in lux) from 2,500 to 10,000 lux. Instructions for treating SAD with light therapy vary depending on the source and intensity of the light and your response to light therapy.

Medicine

Antidepressant medicines can help treat seasonal affective disorder. Your healthcare provider will work with you to select the best medicine for your symptoms.

You must take antidepressant medicines daily for 3 to 6 weeks to get full benefit from them.

There are no nonprescription medicines available to treat seasonal affective disorder.

Psychotherapy

Seeing a mental health therapist in addition to light therapy may be helpful with seasonal affective disorder.

Complementary Treatments

Claims have been made that many herbal and dietary products help depression. Omega-3 fatty acids may help to reduce symptoms of depression.

St. John's wort can help mild symptoms of depression. It will not help severe cases of depression.

How long will the effects last?

Usually seasonal affective disorder is a lifelong condition. Seek professional help to overcome or reduce the symptoms.

What can I do to help myself or my loved one?

Maintaining a healthy lifestyle is important to help control seasonal affective disorder. Staying physically and socially active is very important. Maintaining regular sleep and eating patterns will also help you.

To help prevent or reduce the effects of seasonal affective disorder:

• Between fall and spring try to get regular exposure to sunlight.
• Exercise for at least 20 minutes every day, for example a brisk walk.
• Learn which activities make you feel better and do them.
• Talk to your family and friends.
• Eat a healthy diet.
• Do not abuse alcohol or drugs.
• Learn ways to lower stress, such as breathing and muscle relaxation exercises. Lowering stress helps to improve mood.

When should I seek help

Seek professional help if you have symptoms that keep you from doing daily tasks such as work and family responsibilities.

Get emergency care if you or a loved one have serious thoughts of suicide or harming others.

For more information, see:
Depression: Its Many Forms
Depression: Its Symptoms and Treatment