Frequencies of seasonal major depressive symptoms at high latitudes.

A modified depression rating scale was distributed to a sample of the adult Finnish population (n = 1000) in November 1991. No dependence on latitude (60 degrees N-70 degrees N) was seen in the occurrence of depression. The depressed subjects (n = 54) were reevaluated the following May, and four cases with seasonal affective disorder were found. The results suggest that high latitudes with large variations in the daily lightperiod may not be responsible for high prevalence of major depression with a seasonal pattern.