Seasonal Affective Disorder (SAD)

What is seasonal affective disorder (SAD)?

Seasonal affective disorder (SAD) is a type of depression that happens during certain times of the year. For many people, symptoms start in the winter when daylight hours are shorter. But SAD can also occur during other seasons, like summer.

Anyone can get seasonal affective disorder (SAD), but it's more common in:

• Women.
• People who live far from the equator, where winter daylight hours are very short.
• Adults. It is less likely in children, teens, or older adults.
• People who have other mood disorders, such as depression.

What causes it?

Experts aren't sure what causes SAD. But they think it may be caused by a lack of sunlight. Lack of light may upset your "biological clock," which controls your sleep-wake pattern and other circadian rhythms. Lack of light may also cause problems with serotonin, a brain chemical that affects mood.

What are the symptoms?

Seasonal affective disorder (SAD) may follow a seasonal pattern. For many people, symptoms start in the fall or winter and get better in the spring or summer. Less commonly, some people have symptoms in the spring or summer that get better during the fall or winter. The pattern may repeat, but it may not occur every year.

What are the symptoms?

If you have SAD, you may feel sad or lose interest in activities you usually enjoy. You may have changes in sleep or appetite, low energy, or trouble focusing. You may feel slowed down or restless. Some people feel worthless or guilty. In some cases, thoughts of suicide can happen.

How is it diagnosed?

To diagnose SAD, your doctor will ask if:

• You have been depressed before during the same season and have gotten better when the seasons changed.
• You have symptoms of depression during certain seasons, including feeling sad often and losing interest in activities you usually enjoy.
• You have other mental health conditions, such as generalized anxiety disorder.

Your doctor may also do a mental health assessment to get a better idea of how you feel and how well you are able to think, reason, and remember. It can sometimes be hard to tell the difference between SAD and other types of depression. Many of the symptoms are the same.

How is SAD treated?

Light therapy is the main treatment for SAD. Medicines and counseling may also help.

• Light therapy. The most common light therapy involves sitting in front of a light therapy box, which emits bright white lights, for about 20 to 30 minutes first thing in the morning. Experts think it works by resetting your biological clock.
• Dawn simulation. This is done while you sleep. A low-intensity light turns on at a set time in the morning before you wake up. It slowly gets brighter.
• Antidepressants. Antidepressant medicines may help people who have SAD. They may be used alone. Or they may be used with light therapy.
• Counseling. Some types of counseling can help you manage your symptoms. They can also help prevent future episodes. For example, cognitive behavioral therapy may help.