Seasonal affective disorder (SAD) is though to be a consequence of the decreasing hours of sunshine. In general, lower latitude lead to high tempereture and longer hours of sunshine.
Naze City is loacated at a low latitude (28ﾟN), although the mean hours of sunshine are 1,436 hours per a year, the shortest in Japan. The former study using SPAQ (Seasonal pattern assessment questionare) indicate low prevalence of SAD contrary to expectaion and the possibility of high prevalence of summer depression.
There was however no report of summer depression in Naze, we intended to presume the prevelance of summer depression in Naze. Questionnaire of self-rating scale for mood including CES-D,Mania scale, Atypical symptom scale for SAD and seasonality score scale were delivered 600 midle-aged parents of each 100 highschool students in Naze, Kagoshima and Akita. This self-rating was carried out four times a year at May, August, October and Feburary to determine the seaonal alteration.
Of the self-rating sacale for mood, depression scale of CES-D was cahnged seasonally, but the others were not cahnged. These sesonal alteration of mood differed in Akita City, although in Naze there were no alterations and in Kagoshima City there is tendency of seasonal alterations.
CES-D score and seasonality score had a relationship to hours of sunshine and no relationship to temperature.
These results suggest that the prevelance of summer sepression in Naze would be lower.