title: Age at puberty and mental illness. Towards a neurodevelopmental aetiology of Kraepelin's endogenous psychoses.
abstract: The hypothesis of a neurodevelopmental aetiology of manic-depressive psychosis and schizophrenia is based on the relation between onset of puberty and the final regressive events in the central nervous system (elimination of 40% of neuronal synapses), and the discrepancy in body build in the two disorders which is similar to that between early- and late-maturing individuals. The marked rise in manic-depressive psychoses and decline in schizophrenia, particularly the non-paranoid categories, accompanying the decline in mean pubertal age by some four years during the past hundred years are taken as evidence that manic-depressive psychosis affects early maturers and schizophrenia particularly affects late maturers. Gender differences and social differentials accord with this theory. Redundancy of neuronal synapses characterises manic-depressive psychosis, and reduced density of synapses is a characteristic of schizophrenia, whereas 'normality', with optimal synaptic density, is in between.
authors.affiliation: National Case Register, Oslo, Norway.
authors.forename: L F
authors.initials: LF
authors.lastname: Saugstad
mesh_terms: D000367:Age Factors; D001714:Bipolar Disorder / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology; D006801:Humans; D011606:Psychosexual Development / Q000502:physiology*; D011627:Puberty / Q000502:physiology*; D012307:Risk Factors; D012559:Schizophrenia / Q000503:physiopathology*; D013569:Synapses / Q000502:physiology