Seasonal Affective Disorder


Cabin fever we used to call it. Come the middle of winter you might find yourself going a little stir crazy from cold weather and short, gloomy days. Is this just an inevitable part of the season, or could there be more behind it? You possibly could be struggling with a condition known as Seasonal Affective Disorder.

What is Seasonal Affective Disorder?

Seasonal Affective Disorder (SAD) is a mood disorder characterized by depression that is related to seasonal fluctuations in the amount of daylight. SAD is found most often in locales that are farthest from the equator, such as the extreme northern and southern latitudes. It is also most common from late autumn through early spring, with January and February typically being the months with the highest incidence in the Northern Hemisphere.

SAD was first identified in 1845, but was not officially labeled until the late 1980’s. It is estimated to afflict approximately 10 million Americans. Another 25 million, or about 10-20% of the population, suffer from a milder form of SAD known as sub-syndromal SAD or S-SAD (sometimes called the “winter blues” or “winter blahs”). The onset of SAD is most often during young adulthood, but it is rarely found in people under the age of 20. SAD is also more common amongst women than men.

What Causes Seasonal Affective Disorder?

SAD is a seasonal, cyclic condition, which are conditions where symptoms appear during certain seasons, and disappear or lessen during others. The exact cause of SAD is not known, but we do know that it is related to the amount of sunlight one receives. One of the clues that point to this factor is that SAD is more common in people that live in areas where there is a greater seasonal variance in the amount of daylight and darkness. SAD is rarely found near the equator, where the amount of daylight is almost constant year round.

The internal biological clocks of plants and animals are known to be affected by seasonal changes in the amount of daylight.  This phenomenon is referred to as “circadian rhythm” and is responsible for such things as changing growth patterns in plants and reproductive cycles and hibernation in animals. Changes in the amount of sunlight are thought to affect us humans in similar ways. It is more complex for people in modern times because we are not dependent only on outdoor lighting to influence our cycles. We live in a 24-hour society that often blurs the distinction between night and day, and our unnatural day/night cycles may help to exacerbate such conditions as SAD by artificially manipulating our sleep cycles. Back before electricity and indoor lighting, folks tended to rise with the sun, and go to bed when it got dark. Daylight Savings Time has also been implicated as a factor in throwing off our biological clocks. I remember my uncle, who was a farmer, complaining about how DST would knock his dairy cows all out of wack and affect their milk production. I don’t think he was too thrilled about having to get up earlier to milk them either!

A hormone secreted by the pineal gland of the brain called melatonin plays a key role in regulating our internal clocks and our sleep cycles. It works by making us feel “sleepy” at night.  Melatonin levels are affected by the amount of daylight we are exposed to. Thus there is more melatonin in our bodies during the winter months when the days are shorter. Some researchers believe that the excess melatonin in some people during this time of year can lead to SAD related symptoms such as drowsiness or depression. Another theory speculates that due to our indoor lifestyles that extend our “days” beyond the normal number of winter daylight hours (see discussion above), our circadian rhythms become out of sync. This may lead to long-term abnormalities in the amount of melatonin our bodies produce.

Another theory focuses on the role of serotonin in SAD. Serotonin is a specialized brain chemical, specifically a neurotransmitter, that is responsible for, among other things, helping to regulate our moods. Production of serotonin is stimulated by sunshine, and therefore many people experience lower levels of serotonin during the winter. Serotonin is a known factor in other types of depression, and so is suspected in SAD as well.

A variation of SAD is sometimes observed whereby folks experience SAD-like symptoms in the spring or summer. This can be accompanied by episodes of mania or hypomania (mania to a lesser degree) in the summer, resulting in such things as hyperactivity, grandiose thoughts, or inappropriate enthusiasm. This form of SAD is referred to as “Reverse SAD” or “Summer SAD,” and is only found in about 10% of SAD cases.

What Are the Symptoms of Seasonal Affective Disorder?

The classic symptoms of SAD are as follows:

  • Depression: sadness for no apparent reason, apathy, emotional numbness
  • Anxiety
  • Lethargy, loss of energy
  • Fatigue
  • Irritability
  • Headaches
  • Drowsiness, difficulty staying awake during the day
  • Sleeping too much
  • Isolation and social withdrawal
  • Loss of interest in usually enjoyable or pleasurable activities
  • Lowered libido
  • Difficulty concentrating and organizing thoughts
  • Increased appetite, overeating
  • Increased cravings for sweets and simple carbohydrates
  • Weight gain
  • Difficulty maintaining normal daily schedule and responsibilities

Typical symptoms of Reverse SAD or Summer SAD include:

  • Mania or hypomania, persistently elevated mood
  • Insomnia
  • Irritability
  • Anxiety
  • Decreased appetite
  • Weight loss
  • Increased libido

Diagnosis of SAD is often difficult because many of the symptoms can mimic other forms of depression. To further complicate diagnosis, SAD may also be found in individuals who already have existing conditions that share similar symptoms.  Generally, the identifying characteristics that must be present to justify a diagnosis of SAD are:

  • Periods of depression and other SAD-related symptoms followed by nondepressed periods that come and go in seasonal cycles
  • No other apparent explanation for the symptoms (may not apply in dual diagnosis cases as discussed above)
  • The same patterns exhibiting themselves for at least two consecutive years

What Treatments Are Available for Seasonal Affective Disorder?

By far the most popular treatment for SAD is “phototherapy” or “bright light therapy.” This involves exposing individuals to bright artificial lighting for a prescribed amount of time each day to compensate for the lack of natural daylight in the winter. This therapy uses a device called a light box that is usually composed of a set of fluorescent bulbs with a metal reflector behind them, and covered by a plastic screen. Depending on the intensity of the lights, a light box can provide exposure of up to 20-50 times that of ordinary indoor lighting. Patients are instructed to sit in front of the light for about 30 minutes per day from autumn through spring, usually in the morning hours. Typical light boxes put out about 10,000 lux, or 50 times the brightness of indoor lighting. The boxes can be mounted on the wall or above a table, thus allowing patients to do other things such as eat breakfast or read during the treatment. The main goal of this treatment is to decrease the body’s production of melatonin. This has been proven effective in several studies. Many patients (up to 70%) also find that their symptoms, especially depression, are helped by the treatments. Some have stated that they really look forward to them every day.

However, there are some drawbacks to phototherapy. Some individuals may experience side effects such as eyestrain, headaches, sunburn, irritability, and insomnia. In rare cases, hypomania can occur for some people as well. Another thing to consider is the cost. Not all insurance companies will cover phototherapy, and the cost of a light box can be quite high ($200-$300), in addition to significantly increasing your electric bill. One option that is helpful for many, and much more economical, is to install “full-spectrum lighting” in your home or office. Full-spectrum lighting is accomplished by the use of special light bulbs that more closely reproduce natural sunlight. These are more expensive than regular bulbs, but not as expensive as phototherapy equipment.

Another way SAD is being treated is by giving patients small doses of melatonin in an effort to reset their internal clock. This is a relatively new therapy, and more studies need to be done. But the preliminary results are promising.

Mainstream medical also prescribes medications to deal with SAD, as they do with other types of mood disorders. I do not recommend medications for any medical condition, unless absolutely necessary and appropriate for your specific situation. Phototherapy and other “noninvasive” treatments are definitely the preferred route to go. However, I think it is important to understand what is available and what drugs a patient may be offered. It is also important to understand the risks and possible side effects involved. There are four major classes of mood disorder drugs that are given to SAD patients:

  • Heterocyclic antidepressants (HCAs):  These types of drugs include amitriptyline (Elavil). They help the body to boost serotonin levels. They have a host of side effects, one of which is “tardive dyskinesia.” This results in abnormal mouth movements, abnormal tongue movements, and involuntary movements (ticks) in other parts of the body. Tardive dyskinesia is often permanent in many people.
  • Selective serotonin reuptake inhibitors (SSRIs):  These include Prozac, Paxil, and Zoloft.  Side effects may include psychosis, suicidal thoughts, and convulsions. Pretty scary drugs. I would definitely think twice before putting this stuff into my system.
  • Monoamine oxidase inhibitors (MAO inhibitors):  Drugs such as Nardil and Parnate. Be very careful what you eat if you are taking these. Certain foods high in a substance called “tyramine,” such as some cheeses, wines, pickles, and nasal decongestants, can trigger a spike in blood pressure that has led to strokes in some people.
  • Lithium is often prescribed. This is also given to sufferers of “bipolar disorder.” SAD is often co-diagnosed along side bipolar disorder. Lithium can cause serious kidney and thyroid damage.

Allow me to suggest some practical steps to managing SAD that may prevent having to ingest these dangerous medications:

  • Get outside on a regular basis in the winter, especially on sunny days. Studies have shown that an hour of walking in the sunshine can be just as beneficial as two and a half hours in front of a light box.
  • Get regular exercise. Walking is a great choice, and do it outdoors if possible.
  • If you are able, take a winter vacation to a warm, sunny location. If you have Summer SAD, retreat to a cool place for some rest and relaxation.

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