Seasonality of birth in patients with mood disorders in Japan.
BACKGROUND
Findings about seasonality of birth in individuals with mood disorders have been inconsistent.


METHODS
Data were collected from the governmental statistics, the Patient Survey in Japan in 1996. The number of patients with mood disorders was 13,969. We obtained information about each patient's date of birth, sex, and diagnosis according to ICD-10. Distributions of monthly birth numbers of patients with mood disorders were compared to those of the general population.


RESULTS
Birth excess was observed from winter to early-spring in both sexes, compared to births of the general population. The magnitude of the excess was larger in females than in males. Although the same tendencies were observed in patients with bipolar disorder and depressive disorder, the differences were more marked in females.


CONCLUSIONS
Insufficient birth data in the general population before 1940 and hospital diagnosis.


CONCLUSIONS
Among Japanese patients with mood disorders, there are excess births from winter to early-spring, compared to the general population. This difference is more marked in females than in males.
Mino
Y
Y
Department of Hygiene and Preventive Medicine, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama, Japan. yoshmino@med.okayama-u.ac.jp
Oshima
I
I
Okagami
K
K
D000328:Adult; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007743:Labor, Obstetric; D008297:Male; D011247:Pregnancy; D016574:Seasonal Affective Disorder / Q000175:diagnosis* / Q000453:epidemiology* / Q000523:psychology; D012621:Seasons