Seasonal affective disorder (SAD)
DEFINITION
Seasonal affective disorder (SAD) is a type of depression that’s related to changes in seasons — SAD begins and ends at about the same times every year. If you’re like most people with SAD, your symptoms start in the fall and continue into the winter months, sapping your energy and making you feel moody. Less often, SAD causes depression in the spring or early summer.
Treatment for SAD may include light therapy (phototherapy), psychotherapy and medications.
Don’t brush off that yearly feeling as simply a case of the “winter blues” or a seasonal funk that you have to tough out on your own. Take steps to keep your mood and motivation steady throughout the year.
CAUSES
The specific cause of seasonal affective disorder remains unknown. Some factors that may come into play include:
- Your biological clock (circadian rhythm). The reduced level of sunlight in fall and winter may cause winter-onset SAD. This decrease in sunlight may disrupt your body’s internal clock and lead to feelings of depression.
- Serotonin levels. A drop in serotonin, a brain chemical (neurotransmitter) that affects mood, might play a role in SAD. Reduced sunlight can cause a drop in serotonin that may trigger depression.
- Melatonin levels. The change in season can disrupt the balance of the body’s level of melatonin, which plays a role in sleep patterns and mood.
SYMPTOMS
In most cases, seasonal affective disorder symptoms appear during late fall or early winter and go away during the sunnier days of spring and summer. However, some people with the opposite pattern have symptoms that begin in spring or summer. In either case, symptoms may start out mild and become more severe as the season progresses.
Major depression
Seasonal affective disorder is a subtype of major depression that comes and goes based on seasons. So symptoms of major depression may be part of SAD, such as:
- Feeling depressed most of the day, nearly every day
- Feeling hopeless or worthless
- Having low energy
- Losing interest in activities you once enjoyed
- Having problems with sleeping
- Experiencing changes in your appetite or weight
- Feeling sluggish or agitated
- Having difficulty concentrating
- Having frequent thoughts of death or suicide
Fall and winter SAD
Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:
- Irritability
- Tiredness or low energy
- Problems getting along with other people
- Hypersensitivity to rejection
- Heavy, “leaden” feeling in the arms or legs
- Oversleeping
- Appetite changes, especially a craving for foods high in carbohydrates
- Weight gain
Spring and summer SAD
Symptoms specific to summer-onset seasonal affective disorder, sometimes called summer depression, may include:
- Depression
- Trouble sleeping (insomnia)
- Weight loss
- Poor appetite
- Agitation or anxiety
Seasonal changes in bipolar disorder
In some people with bipolar disorder, spring and summer can bring on symptoms of mania or a less intense form of mania (hypomania), and fall and winter can be a time of depression.
When to see a doctor
It’s normal to have some days when you feel down. But if you feel down for days at a time and you can’t get motivated to do activities you normally enjoy, see your doctor. This is especially important if your sleep patterns and appetite have changed or if you feel hopeless, think about suicide, or turn to alcohol for comfort or relaxation.
