Every Day

January - April 2006 Issue

The Winter Doldrums? Recognizing SAD

Carlyle Chan, MD

Medical College of Wisconsin Psychiatrist;
Vice Chair, Professional Development and Educational Outreach,
Department of Psychiatry and Behavioral Medicine

Winter brings shorter, grayer days, longer nights and for many, the winter blahs. But for a significant number of Americans, winter brings amore serious form of depression called Seasonal Affective Disorder or SAD. Carlyle Chan, MD, talks about SAD, its symptoms and treatment.

Q. What is Seasonal Affective Disorder (SAD)?

Seasonal Affective Disorder is actually a form of depression and it's characterized by people who get depressed primarily during the winter months, starting in October, November and through, say, March. There are some people who get depressed regularly during the summer, but that's a smaller population.

Q. What causes SAD?

We really don't know for sure what causes it. We used to think that because it seemed to be occurring when there was less sunlight, that it was caused by some type of a shift in the circadian rhythms of the body, but there's some conflicting data. There's also evidence that melatonin increases in the winter time, and there's evidence that serotonin, another chemical in the brain, is produced less during thewinter months. There also seems to be some genetic factors, in the sense that some of this seems to run in families. But exactly what causes SAD, we can't say with absolute certainty.

Q. What are the signs and symptoms?

Generally, it's characterized by the depression coming on a regular basis during the winter months. There are many symptoms of depression, but some are more common in SAD. In depression, many of us might have difficulty sleeping or sleep more, while SAD is more characterized byincreased sleeping. Where a lot of depressed patients might have loss of appetite or weight loss, SAD is more characterized by overeating, carbohydrate craving and gaining weight during these winter months. Those are a couple of the symptoms that seem to distinguish it from regular depression, as well as the seasonal timing.

SAD is really more characterized by the fact that the depression seems to occur in the winter months on a regular basis. The official diagnostic criteria call for symptoms to occur two winters in a row, essentially to make sure there is a pattern.

Specifically, SAD is depression, and depression is characterized by symptoms severe enough to interrupt a person's life. In general, symptoms of depression include either weight loss or weight gain and sleeping more or less. Some people slow down in their movements, others feelmore agitated. Some people are tired and some might feel guilty about things or feel worthless. They might have problems concentrating and they may be having thoughts of death. Those are the general symptoms of depression. A person with SAD can have any or all of the symptomsof depression or of SAD. Other people might have some down days, but they keep going to work, they keep their relationships, they keep doing their normal activities, and they manage to keep going.

Q. What treatment options are available?

When it was first reported in 1986, researchers found that bright light therapy seemed to help. At first they thought it had tobe full spectrum sunlight, but now they've come to understand that it needs to be bright light, and studies are constantly being refined.

Most studies of light therapy have been done with light boxes that emit 10,000 lux of light (a lux is a unit of lightness) and 2,500 lux is a minimum. If you think about the fact that a bright sunny day is about 100,000 lux and that standard lighting in a house is about 200 to 300 lux, then you get an idea that you need to increase the intensity and brightness of the light quite a bit. Not as bright as bright sunlight, but at least 50 fold from standard house light for the therapy to be effective.

Initially, researchers thought it would be better to be exposed to this in the morning, now it's not so clear again. Some people do better in morning light and others do better with the light therapy in the evening, but the threshold seems to be about 10,000 lux for about 30 minutes a day. If you have a light that's 2,500 lux, then you need to spend about 2 hours a day in that light. You could be doing your work or be at your desk or reading the newspaper. You need to be close to the light source to get the full effect because the brightness effect dissipates very quickly the farther away you get from the light source.

As another form of light therapy, some doctors recommend taking a walk outside, even on a cloudy day, during the noon hour. It can give you a lot more exposure to bright light than even a light box sometimes. Especially on sunny days, if you can spend more time outside, it's probably better.

The condition also seems to respond to antidepressant medication, especially serotonin reuptake inhibitors. Most of the research was done with fluoxetine and sertraline, but there's a feeling that most of the other antidepressants are effective in this disorder as well.

There was just a recent study published with about 60 people that seemed to indicate that cognitive behavior therapy (talk therapy or psychotherapy) might also be of some help with this disorder, but that's an early study that needs to be replicated.

Q. Why does light therapy work?

With light therapy, we're not quite certain why it works. It's just like the causes: there are a number of different theories that somehow it changes the circadian rhythm or it can affect melatonin secretion. We're not sure why it works.

The light box is not FDA regulated, so there are all sorts of companies that make them. In general, they are safe, but there are side effects. Some people get eye strain or visual disturbances; some people get headaches; and some people feel a little wired with the lights. So it's not without side effects that some people don't tolerate as well. Some people don't care for the fluorescent light boxes as much as the similar full spectrum light. It's just a matter of personal preference.

Q. How common is SAD?

There seems to be data — again initial data was stronger than more recent data — that it occurs in between roughly 1 percent and 10 percent of the population, and that 10 percent is more common in northern states than in southern states. It seems to fit with the amount of sunlight people get. It also seems to affect females a little bit more frequently.

Q. Is it normal to feel a little down in the winter?

There does seem to be less severe forms of the disorder. People talk about getting the January blahs or the January blues. It’s quite possible that many people aren’t incapacitated by SAD, but just feel a little bit more down in the dumps during these months of gray days.

Q. What else should people know about SAD?

There may end up being different reasons why people get depressed in the winter time and it may vary from person to person, but we don’t have any definitive data.

If it’s not a severe form of depression, it’s not disruptive and you have the money to buy a light box, then you might experiment with it. But if it’s really disrupting your life, then it may be useful to get a full evaluation because it may not be depression causing the mood swings or other symptoms. There may be other physical things going on, and it’s important to get an assessment, particularly if it’s quite disruptive in a person’s life.

Author: Carlyle Chan, MD

Source: Every Day

Date: January - April 2006 Issue