Recurrent brief depression and its relationship to seasonal affective disorder.

Recurrent brief depression (RBD) and seasonal affective disorder (SAD) have been both recently described as subgroups of major depression (DSM-III-R). We have established a relationship between these two syndromes in a cohort of 42 outpatients who presented themselves to a clinic for seasonal affective disorder at the Psychiatric Department of the University of Bonn, FRG. Our preliminary data indicate that 31% of the patients who were diagnosed as suffering from either SAD or its subsyndromal form (S-SAD) can also be categorized as RBD (RBD-seasonal) in a 1-year observation period. During the time span of 1 year RBD-seasonal patients had a mean number of 20 (SD 9) episodes compared with 6 (SD 5) episodes (P less than 0.001) in the group of seasonal patients without BRD. These episodes were accentuated in fall/winter and outnumbered those in spring/summer significantly (P less than 0.001). The mean duration of each episode was 4.6 (SD 2.6) days in the RBD-seasonal group and 21.8 (SD 29) in the non-RBD-seasonal group. Patients with RBD-seasonal experienced seasonal changes as more of a problem and reported a lower percentage of first-degree relatives with a history of depression than the non-RBD-seasonal group.