Mental health articles

Seasonal affective disorder (SAD) was recognized as a distinct disorder by Rosenthal and colleagues only in the mid-1980s . DSM-IV-TR considers it to have the following symptoms and characteristics:

a regular temporal relationship between the onset of an episode of depression and a particular time of year

full remissions occur at regular times of the year

two major depressive episodes that meet these criteria have occurred in the previous two years

any seasonal depressive episodes outnumber the number of nonseasonal episodes of depression.

The characteristics of SAD appear to be quite different from major depression, and include increased appetite, weight and duration of sleep, as well as other depressive symptoms including sadness, decreased activity, anxiety, work problems, decreased libido, and day-time tiredness. The depression is seldom severe enough to require absence from work. Winter episodes typically begin in November and last about fi ve months.

Age of onset is typically between the ages of 20 and 30 years. It may prove a chronically recurring problem: up to 42 per cent of patients have recurring episodes for up to 11 years following initial onset, some of which may occur in winter and some of which may become non-seasonal. The prevalence of SAD varies between less than 1 per cent and more than 10 per cent depending on the country in which rates are measured. In the northern hemisphere, prevalence rates are higher in northern countries, and lower in southern countries. Symptoms get worse if people move from south to north and improve if they move in the opposite direction. The opposite pattern occurs in the southern hemisphere.

Those whose symptoms are so severe that they receive a diagnosis of SAD may be a subset of a larger group of people who experience a variety of negative symptoms over the winter. Less dramatic seasonal changes in activity and weight levels occur within the general population. Terman, for example, reported that 50 per cent of the general population reported lowered energy levels, 47 per cent reported increased weight, while 31 per cent reported decreased social activity in the winter months. Twenty-five per cent reported that these changes were suffi ciently marked to signify a personal problem.

Tags: disorder, sad symptoms, seasonal affective disorder, symptoms