Answer B. Circadian rhythm
There might be an optimal specific time at which to administer light treatment because of a correlation between the timing of the internal body clock and the optimal timing of light administration.
Symptoms associated with SAD are recurrent wintertime sadness, decrease in activity, social difficulties (eg, withdrawal), anxiety, irritability, occupational difficulties, and daytime tiredness. Most patients with winter SAD also report a seasonally recurrent increase in sleep, weight, and appetite; carbohydrate craving; and decrease in libido.More realistic than moving to a sunny climate, the leading treatments are medication or various forms of light therapy.
There have been extensive studies and debates over the optimal timing, duration, and intensity of bright light therapy. Although there are individual exceptions, early morning light therapy for under an hour at 10,000 lux intensity provides good results. The intensity can be reduced to 2500 lux (by increasing the distance to the light) if glare makes the brighter light uncomfortable. Thirty-minute sessions are a typical starting duration, which can be adjusted upward or downward depending on clinical response.
For related content, please see “Update on Seasonal Affective Disorders: Clinical Issues and Treatment Strategies,” by Dan A. Oren, MD, on which this quiz was based.