Evidence for a seasonal form of recurrent brief depression (RBD-seasonal)

We have established a relationship between recurrent brief depression (RBD) and seasonal affective disorder (SAD) in a cohort of 42 outpatients who presented themselves at a clinic for seasonal affective disorder at the Psychiatry Department of the University of Bonn, Germany. 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) for a 1-year observation period. During the time span of 1 year, RBD-seasonal patients had a mean number of 20 +/- 9 episodes, which were accentuated in fall/winter, outnumbering the ones in spring/summer significantly (P < 0.001). The mean duration of each episode was 4.6 +/- 2.6 days in the RBD-seasonal group. RBD-seasonal patients 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.