SEASON AND MENTAL-ILLNESS IN AN ARCTIC AREA OF NORTHERN FINLAND

The seasonal variation in mental disturbances was examined in 1251 rei ndeer herding males in an arctic area of northern Finland using the ps ychiatric section of the Cornell Medical Index questionnaire (CMI-MR). The mean age of subjects was 43 years. One third of them were full-ti me reindeer herders and 1/10 were Lapps. The prevalence of mental diso rders (CMI-MR at least 5) was estimated at 14 %, and it showed peaks i n spring and autumn. The pattern was repeated for different varieties of illness, except for depression which showed a single cycle with the highest prevalence in the light season. The authors conclude that men tal disorders in the arctic are most common in spring and autumn, and they question the common belief in mid-winter as the most common seaso n for mental disorders.