DR. ANTHONY LEVITT is the chief of psychiatry at Sunnybrook Health Sciences Centre in Toronto where he focuses his research on several related areas within the field of mood disorders.
With clocks turning back on Nov. 7 this month and days getting shorter, we tracked down Dr. Levitt for a chat about seasonal affective disorder (SAD).
What time of year usually marks the onset of symptoms?
Patients often begin to feel symptoms as early as October or late September. Full episodes usually occur by December.… Usually by the end of March or April the symptoms are gone. But many people can’t work during those months, as in regular depression, so it impairs function much the same way.
Is it just the lack of light that causes SAD?
We don’t really have evidence that it’s solely the lack of light. We do know that by using light therapy people feel better, but that doesn’t mean that’s what causes the depression. We treat pneumonia with penicillin, but that doesn’t mean a lack of penicillin causes pneumonia.There are a lot of things changing in winter: light, the temperature drops, the wind pressure changes. We do know there are annual events — Christmas, for example — that trigger depression as well.
Annual events occur in spring and summer, too, but we don’t see the same incidences of depression.
That’s a very good point. That tells us that — at least in part — there is some sort of geoclimatic component.
How much sunlight do we need every day?
There’s really no specific number or amount that is right for everybody.
Can’t we just mimic that light by turning on lamps?
Well, not really because light has many different qualities: wavelength, frequency, intensity. Natural sunlight has a broad range toward red and orange. Incandescent light uses more yellow. Of course there are broad spectrum lights.…
As with light therapy?
Yes.There’s research that shows that patients who are exposed to very vivid, broad spectrum light for a few hours every day have a decreased incidence of seasonal affective disorder.So sitting in front of a light box for an hour or half an hour, usually in the morning, is often a popular treatment for symptoms. There’s even a head-mounted version, but we recommend that people don’t move around too much when using it.
Where does Canada fall when it comes to cases by the area?
Well, the further away you are from the equator the higher the rate. Canada does have a higher rate. It’s estimated that two and a half per cent of the population have seasonal affective disorder. It’s higher than schizophrenia; it’s higher than bipolar disorder. In terms of chronic illness, that’s a large number.
What role does excessive alcohol consumption play?
The issue is drinking in moderation. Excessive drinking, drinking large amounts in a short period of time, can affect treatment.But drinking in moderation doesn’t seem to be a large issue.
What if they want to stay away from pharmaceuticals?
There are a number of products in health stores: St. John’s wort, for example; s-adenosyl methionine, also known as SAM-e; and tryptophan, which is an amino acid that seems to have a positive affect on sleep. Some people use melatonin and swear by it.
For someone who is prone to SAD, what happens to that person the rest of the year?
Good question. If you have a mental health condition, you are at risk for others. People with depression also develop some kind of an anxiety disorder as well. And it’s not to say that people with seasonal depression are immune to non-seasonal depression as well.
What steps should people take to prevent SAD?
By making sure you have a system in place that includes light exposure and in the spring and summer months preparing foods that don’t have high-carbohydrate levels, maintaining an exercise regime during the winter months. None of these are foolproof, of course, but they do seem to help. If you know it’s something you are prone to, it’s best to start medication and light therapy prior to the onset.
