Seasonal Affective Disorder (SAD)

Seasonal affective disorder (SAD) is a type of depression that’s related to changes in the season, it begins and ends at about the same times every year. If you are like most people with SAD, your symptoms may start in the fall and continue into the winter months, sapping your energy and making you feel moody. Less often, SAD can cause seasonal depression in the spring or early summer.

Treatment for SAD may include light therapy, medications, and psychotherapy.

Do not brush off that yearly feeling as simply a case of the “winter blues”. Take steps to keep your mood and motivation steady throughout the year.


In most cases, seasonal depression appears during late fall or early winter and goes away during the sunnier days of spring and summer. Less commonly, 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.

Signs and symptoms of SAD may include:
• Feeling depressed most of the day, nearly every day
• Losing interest in activities you once enjoyed
• Having low energy
• Having problems with sleeping
• Experiencing changes in your appetite or weight
• Feeling sluggish or agitated
• Having difficulty concentrating
• Feeling hopeless, worthless, or guilty
• Having frequent thoughts of death or suicide

Fall and Winter SAD

Symptoms specific to winter-onset SAD, sometimes called winter depression, may include:
• Oversleeping
• Appetite changes, especially a craving for foods high in carbs
• Weight gain
• Tiredness or low energy

Spring and Summer SAD

Symptoms specific to summer-onset seasonal depression may include:
• Trouble sleeping (insomnia)
• Poor appetite
• Weight loss
• Agitated or anxiety

Seasonal Changes in Bipolar Disorder

In some people with bipolar disorder, spring and summer can bring symptoms of mania or a less intense form f mania, and fall and winter can be a time of depression

When to See a Doctor

It is 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, you turn to alcohol for comfort or relaxation, or you feel hopeless or think about suicide.


The specific cause of SAD remains unknown. Some factors that may come into play include:
• Your biological clock. 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 might play a role in seasonal depression. Reduced sunlight can cause a drop in serotonin which 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.

Risk Factors

Seasonal depression is diagnosed more often in women than in men. And SAD occurs more frequently in younger adults than older adults.

Factors that may increase your risk of seasonal affective disorder include:
• Family history. People with SAD may be more likely to have blood relatives with SAD or another form of depression.
• Having major depression or bipolar disorder. Symptoms of depression may worsen seasonally if you have one of these conditions.
• Living far from the equator. SAD appears to be more common among people who live far north or south from the equator. This may be due to the decreased sunlight during the winter and longer days during the summer months.


Take signs and symptoms of seasonal depression seriously. As with other types of depression, SAD can get worse and lead to problems if it’s not treated. These can include:
• Social withdrawal
• School or work problems
• Substance abuse
• Other mental health disorders such as anxiety or eating disorders
• Suicidal thoughts or behavior

Treatment can help prevent complications, especially if SAD is diagnosed and treated before symptoms get bad.