Seasonal affective disorder (SAD) is an older term for major depressive disorder (MDD) with seasonal pattern. It’s a psychological condition that results in depression, normally provoked by seasonal change. People typically experience the condition in winter. The condition most often occurs in women and in adolescents and young adults.
The exact cause of SAD (MDD with seasonal pattern) is unknown. Contributing factors can vary from person to person. However, people who live in parts of the country that have long winter nights (due to higher latitudes) and less sunlight are more likely to experience the condition. For example, SAD is more common in Canada and Alaska than in sunnier Florida.
Light is thought to influence SAD. One theory is that decreased sunlight exposure affects the natural biological clock that regulates hormones, sleep, and moods. Another theory is that light-dependent brain chemicals are more greatly affected in those with SAD.
People whose family members have a history of psychological conditions are also at greater risk for SAD.
While SAD affects people differently, symptoms most commonly begin in October or November and end in March or April. However, it’s possible to experience symptoms before or after this time.
In general, there are two types of SAD: wintertime and summertime.
Symptoms of wintertime SAD include:
- daytime fatigue
- difficulty concentrating
- feelings of hopelessness
- increased irritability
- lack of interest in social activities
- reduced sexual interest
- weight gain
Symptoms of summertime SAD include:
- difficulty sleeping
- increased restlessness
- lack of appetite
- weight loss
In severe instances, people with SAD can experience suicidal thoughts.
The symptoms of SAD can mirror several other conditions. These include:
- bipolar disorder
A doctor may recommend several tests to rule out these conditions before they can diagnose SAD, such as thyroid hormone testing with a simple blood test.
A doctor or psychiatrist will ask you several questions about your symptoms and when you first noticed them. People with SAD tend to experience symptoms every year. It’s not typically related to an emotional event, such as the end of a romantic relationship.
Both forms of SAD can be treated with counseling and therapy. Another treatment for wintertime SAD is light therapy. This involves using a specialized light box or visor for at least 30 minutes each day to replicate natural light.
Another treatment option is a dawn simulator. It uses a timer-activated light to mimic the sunrise, which helps to stimulate the body’s clock.
Light therapy should be used only under a doctor’s supervision and on approved devices. Other light-emitting sources, such as tanning beds, are not safe for use.
Healthy lifestyle habits can also help minimize SAD symptoms. These can include:
- healthy diet with lean protein, fruits, and vegetables
- regular sleep
Some people benefit from medications such as antidepressants. These may include medications such as fluoxetine (Prozac) and bupropion (Wellbutrin). Talk to your doctor about which medication may be best to treat your symptoms.
If you experience symptoms associated with SAD, see a doctor, counselor, or psychiatrist.