Seasonal Affective Disorder (SAD),
Winter Blues, and SunSprite


Seasonal depressions usually come on during the fall or winter, when the sun does not rise until 7:30 AM or later. They occur more frequently in higher latitudes, where fall and winter bring later sunrises. They usually vanish in the spring, with the return of early morning light. At the equator, where the sun rises at 6 AM on most days, there is no seasonal depression. 30 years ago, researchers at the National Institute of Mental Health (NIMH) discovered that seasonal depression can be treated by exposure to bright light without awaiting the return of spring. That's where SunSprite comes in.

Seasonal affective disorder (SAD) is a condition in which the seasonal depressions are serious enough to meet the full diagnostic criteria for “major depressive disorder.” In the USA, about 25 million people suffer from SAD, making it hard for them to keep up their regular activities.

SAD must be distinguished from “winter blues,” a seasonal drop in mood that falls short of a major depression. About a third of the US population (100 million people) suffer from feelings of sluggishness and fatigue in the fall and winter. They can go about their normal activities, but they feel less energetic, less focused, a little more down. Like SAD, winter blues also improves with bright light therapy.

Both SAD and winter blues look different from some other types of depression, which have symptoms of decreased appetite, weight loss, and insomnia. By contrast, the depressions of SAD and winter blues look almost like a mild kind of hibernation, with increases in sleep, appetite and weight.

SunSprite can help with both SAD and winter blues. It acts as a reminder to get the right amount of bright light each day. It coaches you to get your bright light at the most effective time of day. You can use it with sunlight or with a therapeutic light box, or as you move between the two while still tracking your “dose” of light based on decades of research about light therapy. SunSprite offers each individual the freedom to get light therapy in a way that suits a person best, whether outdoors or at the kitchen table, with a light box or the sun streaming in through a window.

SunSprite was devised by psychiatrists who know first-hand that many people with SAD and winter blues do not want to take medication, but do want to feel happier, more energetic, and more focused. SunSprite helps take the vagueness out of light therapy, making it easier for the user to keep track of how much light they've received, whether they are using a therapeutic light box or are sitting in a sunny window.