Seasonal Affective Disorder is no stranger to our Yampa Valley. At 40 degrees North latitude, we get 5 ½ hours less daylight in January than we do in July. The further north you go, the less daylight available. No wonder S.A.D. is so common in Alaska!
For reasons not completely understood, S.A.D. is much more common in women than men (about 75:25 ratio), and virtually unknown in kids under 20. It’s a type of depression that can range from a mild problem (usually called "Winter Blues") to a full-blown, even incapacitating illness. Fortunately, it tends to lift if not disappear altogether, once the seasons change and full-sun days return.
Why? What makes exposure to sunlight such a big deal to some people's moods (note that only about half a million Americans experience S.A.D.)? Today's best-guess points to melatonin, a natural hormone produced by the pineal gland in the back of the cranium. Melatonin has important functions in sleep, aging, and regulating our circadian cycle (sleep/awake rotation), among other things. Sunlight is a signal to our brains that it's wake-up time, and in response the pineal gland suppresses melatonin production. But the message to do so comes primarily from the suprachiasmic nucleus, a ganglion just above the retina's optic nerve. Too little light means a weak "shut it down" signal to the pineal, leaving too much melatonin in the bloodstream. Interestingly, recent research has found that other parts of the body (besides the suprachiasmic nucleus) also respond to light exposure, suggesting a direct effect on the bloodstream itself.
The treatment of choice for Seasonal Affective Disorder is bright light therapy – exposing the person to full-spectrum light (minus UV) for short periods of time, 30 minutes or less. This is usually done using a special light box that allows adjustment of light intensity. Of course, exposure to natural sunlight can work as well (think: Mexico), but our local weather may cooperate (and getting out of the office for that blue-sky day is dicey). Even a single session of light therapy can bring results, but most people get real benefit from sessions spread over a few weeks.
Those with S.A.D. typically report a cluster of these symptoms:
If you think you're struggling with S.A.D., you can seek professional help locally or from a specialist in this area or along the Front Range. You can also purchase a Light Box designed for this purpose, usually 10,000 lux with reflector (try here, for example). Or you can take advantage of those opportunities to get outside and suck up the natural light available to you (even overcast days in NW Colorado often have more intense light than that from a Light Box). Exercise has also been shown to be beneficial, so the cheap – and maybe best – cure is probably committing to a regimen of daily walks, best around lunchtime, for at least half an hour.
And remember, summer’s just weeks away!