Beating Seasonal Affective Disorder

You may be suffering from seasonal affective disorder (SAD) If you notice periods of depression that seem to accompany seasonal changes during the year. This condition is characterized by recurrent episodes of depression – usually in late fall and winter – alternating with periods of normal or high mood the rest of the year. However, it can also happen during the summer. This is called Reverse SAD.

Most people with Seasonal Affective Disorder are women whose illness typically begins in their twenties, although men also report SAD of similar severity. SAD can also occur in children and adolescents, in which case the syndrome is first suspected by parents and teachers. Many people with SAD report at least one close relative with a psychiatric condition, which may imply a genetic link.

Symptoms of winter SAD usually begin in October or November and subside in March or April. Some patients begin to slump as early as August, while others remain well until January. Regardless of the time of onset, most patients don’t feel fully back to normal until early May. Depressions are usually mild to moderate, but they can be severe.

The symptoms of recurrent winter seasonal affective disorder include oversleeping, daytime fatigue, carbohydrate craving and weight gain. Also, there are the usual features of depression, such as decreased sexual interest, lethargy, hopelessness, suicidal thoughts, lack of interest in normal activities, and social withdrawal.

Light therapy, described below, is now considered the first-line treatment, and if properly dosed can produce relief within days. Antidepressants may also help, and if necessary can be used in conjunction with light.

In about 1/10th of cases, annual relapse occurs in the summer rather than winter, possibly in response to high heat and humidity. During that period, the depression is more likely to be characterized by insomnia, decreased appetite, weight loss, and agitation or anxiety.

People with such "reverse SAD" often find relief with summer trips to cooler climates. Generally, normal air conditioning is not sufficient to relieve this depression.

In still fewer cases, some people may experience both winter and summer seasonal affective disorder, while feeling fine each fall and spring.

The most common characteristic of people with winter SAD is their reaction to changes in environmental light. People with SAD often say that their depression worsens or reappears whenever the weather is overcast at any time of the year, or if their indoor lighting is decreased.

Seasonal affective disorder is often misdiagnosed as hypothyroidism, hypoglycemia, infectious mononucleosis, and other viral infections.

How is winter SAD treated with light?

Bright white fluorescent light has been shown to reverse the winter depressive symptoms of SAD. Early studies used expensive "full-spectrum" bulbs. Bulbs with color temperatures between 3000 and 6500 degrees Kelvin all have been shown to be effective. The lower color temperatures produce "softer" white light with less visual glare, while the higher color temperatures produce a "colder" skylight hue.

The lamps are encased in a box with a diffusing lens, which also filters out ultraviolet radiation. The box sits on a tabletop, preferably on a stand that raises it to eye level and above. Such an arrangement further reduces glare sensations at high intensity, and preferentially illuminates the lower half of the retina of the eye, which is rich in photoreceptors that are thought to mediate the antidepressant response.

Studies show between 50% and 80% of people show complete remission of symptoms, although the treatment needs to continue throughout the difficult season in order to maintain this benefit.

There are three major dosing requirements of light therapy, and optimum effect requires that the dose be individualized, just as for medications. The three requirements are light intensity, the duration of treatment with light and the time of day the therapy is used.

Light intensity - The treatment uses an artificial equivalent of early morning full daylight (2500 to 10,000 lux), higher than projected by normal home light fixtures (50 to 300 lux). A light box should be capable of delivering 10,000 lux at eye level, which allows downward adjustments if necessary.

Light duration - Daily sessions of 20 to 60 minutes may be needed. Since light intensity and duration interact, longer sessions will be needed at lower intensities. At 10,000 lux – the current standard – 30-minute sessions are most typical.

Time of Day of exposure - The antidepressant effect of light therapy is mediated by light’s action on the internal circadian rhythm clock. Most people with winter depression benefit by resetting this clock earlier, which is achieved specifically with morning light exposure.

Since different people have different clock phases (early types, neutral types, late types), the optimum time of light exposure can differ greatly.

Side effects of light therapy are uncommon. Some people complain of irritability, eyestrain, headaches, or nausea. Those who have histories of hypomania in spring or summer are at risk for switching states under light therapy, in which case light dose needs to be reduced. There is no evidence for long-term adverse effects, however, and disturbances experienced during the first few exposures often disappear spontaneously.

As an important precaution, people with Bipolar disorder – who are at risk for switching into full-blown manic episodes – may need to be on a depression drug while using light therapy.

If your symptoms of seasonal affective disorder are mild – that is, if they don't interfere too much with your daily living, you may want to try light therapy as described above or experiment with adjusting the light in your surroundings with bright lamps and scheduling more time outdoors in winter.

You may also try the natural cures for depression that are effective for many types of depression.

If your depressive symptoms are severe enough to significantly affect your daily living, consult a mental health professional qualified to treat SAD.

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