Season of Birth in the General Population and in Patients with Mental Disorder in Norway

Abstract

It has been shown by Knobloch and Pasamanick that a disproportionate number of oligophrenics are born during the first months of the year. This appears to be true mainly in warmer climates and is supposed to be related to nutritional problems which arise when the most sensitive weeks of pregnancy coincide with the unpleasantly warm summer months. Such findings have led to a revival of the interest in the monthly birth distribution of schizophrenics. There is some evidence that this pattern actually differs from that of the general population, and para-natal complications could be the explanation.