Seasonal Affective Disorder: Causes, Symptoms & Treatments

What is Seasonal Affective Disorder?

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 Seasonal Affective Disorder

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.
• Cause problems with serotonin, a brain chemical that affects mood.

Symptoms of Seasonal Affective Disorder

If you have SAD, you may:

• Feel sad, grumpy, moody, or anxious.
• Lose interest in your usual activities.
• Eat more and crave carbohydrates, such as bread and pasta.
• Gain weight.
• Sleep more but still feel tired.
• Have trouble concentrating.

Symptoms come and go at about the same time each year. Most people with SAD start to have symptoms in September or October and feel better by April or May.

Treatments for Seasonal Affective Disorder

A range of treatments are available for SAD. Your GP will recommend the most suitable treatment programme for you.

The main treatments are:

• lifestyle measures, including getting as much natural sunlight as possible, exercising regularly and managing your stress levels
• light therapy – where a special lamp called a light box is used to simulate exposure to sunlight
• talking therapies, such as cognitive behavioural therapy (CBT) or counselling
• antidepressant medication, such as selective serotonin reuptake inhibitors (SSRIs)