A FOLLOW-UP-STUDY OF SEASONAL AFFECTIVE-DISORDER

Background. The long-term course of seasonal affective disorder has no t been well studied. Method. Using the Structured Clinical Interview f or DSM-III-R, we interviewed 75% of a sample of 124 subjects diagnosed from five to eight years previously as fulfilling DSM-III-R criteria for recurrent major affective disorder, seasonal pattern. Results. In the follow-up period, 38% of the sample continued to fulfil DSM-III-R criteria for seasonal illness; 28% had recurrent major depressive diso rder, but no longer displayed a seasonal pattern; 18% were completely well with no further depression: 6% had subsyndromal symptoms; and 5%, although not meeting DSM-III-R criteria for seasonal illness, were st ill displaying constant periodicity. A short duration of index episode and a high frequency of illness predicted a continuing seasonal cours e of illness. Conclusion. Diagnostic criteria for seasonal affective d isorder need to be further refined, possibly restrictively, if they ar e to be used to predict the future course of seasonal illness.