Seasonal Affective Disorder (SAD)

SAD is a disturbance in biological rhythms triggered by seasons, the outcome of which is the onset or worsening of depressive symptoms. The condition is often chronic and impairing. Most suffer SAD in winter at which time their mood status is often labeled as winter depression or the winter blues, the symptoms of which are listed in Table 1. Research suggests that a causative factor in SAD is the reduction in sunlight hours occurring in winter, which de-synchronisers the body clock and disturbs the circadian rhythm. Although the etiology of SAD is unknown, recent studies have highlighted changes in serotonin levels, a neurotransmitter implicated in depression. In winter, serotonin levels are lower, however winter is not the only season to influence mood. Recently, a form of summer depression has been recognised, the depressed mood being triggered by severe heat and/or intense light.

A standard treatment for winter depression is the use of light therapy that involves sitting in front of a florescent light box with eyes open for a set period. Treatment sessions occurring in the morning have the best result, the outcome being the re - synchronisation of the circulation rhythm and the reduction of winter depression symptoms. Helpful in treating SAD is maximising exposure to natural light thus exercising or working out doors is helpful as is working close to windows and arranging for winter vacations in a warm, sunny climate.

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