Many people talk about not liking winter or having the winter blues, but Seasonal Affective Disorder is much more serious.

What Is Seasonal Affective Disorder?

“SAD is a type of clinical depression that comes and goes with the seasons, at about the same time every year,” said Dr. Anuj Chandra, medical director of the Advanced Center for Sleep Disorders. “For some people, it’s so serious that they are clinically depressed for half of the year.”

For most people who suffer from it, SAD begins in the late fall or early winter when the days get shorter, but smaller numbers of people have seasonal depression in the spring and summer.

Up to 10 percent of people in the United States are thought to have SAD, depending on where they live. For example, surveys show that SAD affects 9.7 percent of people in New Hampshire but only 1.4 percent in Florida. It affects women more than men and becomes more common the further north you go.

How SAD Works

SAD affects people most often during the fall and winter because the amount of sunlight during the day is lower. Sunlight is a major influence on your body’s circadian rhythms, the “internal clock” that sets the timing for many body functions.

Normally, darkness at night signals your brain that it is time for your body to slow down, and bright sun the next morning tells your brain that it’s time for your body to wake up and be alert. In the fall and winter, we get shorter days with fewer hours of sunlight so the body’s internal timing is thrown off.

Experts are not certain why it works that way. One theory is that the way your body produces melatonin changes. Usually, melatonin increases at night to promote sleep then falls in the morning, which helps you wake up. For people with SAD, however, melatonin levels peak later at night and last longer in the morning, making it harder to wake up, causing fatigue during the day, and making it hard to fall asleep at night.

SAD and Sleep

Sleep problems are common for people with SAD, including:

  • Excessive sleepiness during the day
  • Sleeping two hours or more longer at night, compared to the summer months
  • Difficulty waking in the morning
  • Frequent nightmares

“SAD creates a persistent pattern of disturbed sleep,” said Dr. Chandra. “It can be a never-ending cycle of insomnia, poor sleep, and fatigue. All of that makes depression worse.”

The effects can be mild, but for some people, the effects are much more extreme: strong sadness, fatigue, hopelessness, lack of interest in normally enjoyable activities, and social withdrawal.

How to Recognize SAD

How do you know you have SAD?

SAD Has A Seasonal Pattern — Symptoms follow the seasons. SAD typically occurs in the fall and winter, then resolves when the days get longer in spring and summer. Among the small number of people who experience warm weather SAD, the pattern of onset and relief is still seasonal.

SAD Has Daily Symptoms — A SAD diagnosis requires you to experience five symptoms of clinical depression every day over a period of time. If you have fewer symptoms, that doesn’t mean you don’t have a problem, just that you’re not suffering from clinical depression.

Medical Treatment for Seasonal Affective Disorder

If you have Seasonal Affective Disorder (SAD) — marked by moderate to severe symptoms of clinical depression every day for days at a time — you should talk to your doctor.

Bright Light Therapy for SAD — Bright light therapy is often suggested as a treatment for SAD. Most people with SAD benefit from sitting in front of a light therapy box, which produces artificial light that is similar to sunlight, for about 30 minutes early in the morning. You can buy special lights especially for this purpose, but you should not use them without a doctor’s supervision.

“If your SAD is serious enough for bright light therapy, you’re dealing with major depression and you really should not do that alone,” said Dr. Anuj Chandra, medical director of the Advanced Center for Sleep Disorders. “You may need other types of treatment in addition to light therapy, and you may need a doctor to help you use the light therapy box properly.”

Cognitive Behavioral Therapy — This is a form of talk therapy in which a therapist helps you retrain how you think about the darker months when SAD usually occurs. This kind of retraining can help in the short term, while you are experiencing SAD symptoms, and can prevent future symptoms in later years.

Antidepressants — Like other forms of serious depression, SAD can also be treated with a variety of prescription antidepressant medications.

Self-Treatment for Mild Seasonal Mood Changes

If shorter days in fall and winter bring mild changes in mood that are not as serious enough for a diagnosis of SAD, there are steps you can take on your own to feel better.

More Sun — One of the easiest things you can do for more moderate seasonal mood changes is to go outdoors and get some sun. Even if you feel like sleeping later, set your alarm and get up so you can start your day with early morning sun.

Be Active — Once the day is started, if you’re feeling down you still might feel like staying inside. Don’t give in to those feelings. Getting out into the world and being active will help establish — or re-establish — your normal sleep-wake cycle.

Sleep and Seasonal Affective Disorder

Sleep and depression are strongly linked, and the relationship goes in both directions. Sleeping badly can cause negative moods the next day, and insomnia can increase the risk of depression. At the same time, depression can lead to sleep problems.

“Patients very frequently have sleep problems and depression at the same time, and the relationship can be very complex,” said Dr. Chandra. “For example, prescription medications might help depression symptoms but not improve your sleep, and then lingering sleep problems might cause the depression to return. Or the effects of chronic sleep disorders may contribute to depression significantly. Both need to be treated.”

Practice Good Sleep Hygiene

That close relationship between sleep and mental health means that good sleep hygiene is important, whether you’re experiencing SAD or milder “winter blues.” Either way, it’s a good idea to follow these tips on how to get a good night’s sleep:

  • Exercise during the day but not in the evening.
  • Avoid caffeine for several hours before bedtime.
  • Turn off all electronic devices at least one hour before going to bed.
  • Be consistent with your bedtime, routine for going to bed, and morning wake-up time.
  • Keep your bedroom cooler at night than during the day.