[Seasonal predominance in the date of birth in schizophrenia and affective disease].

Since 1929 a world-wide winter predomination of schizophrenic births has been described. A spring predomination for affective disorders has been suggested. A seasonal tendency of births between 1891 and 1967 of 1086 patients fulfilling the ICD-9 criteria for schizophrenia and affective disorders (with the respective subtypes) has been undertaken at the National Institute of Neurology. The control group was made up of patients with neurological diseases paired by age and sex. Analysis was submitted to the Pike and Morrow method. A predomination of births in fall was found for male paranoid schizophrenics. No seasonal tendency was found weather in affective disorders nor in other subgroups. There are various theories which explain these results (atmosphere influence, conception habits, genetic particularities, etc.) The interest rests on the potential prevention and the adequate nosography. Professor Dionisio Nieto proposed this study at the time that he ruled the Psychiatric Division of the National Institute of Neurology and Neurosurgery. We dedicate it to his memory.