DEVELOPMENTAL INSANITY OR DEMENTIA-PRAECOX - WAS THE WRONG CONCEPT ADOPTED

Over a century ago, the Scottish psychiatrist Thomas Clouston proposed the idea of a developmental or adolescent insanity. He characterised the condition as having a male predominance and a poor outcome, and no ted the frequency of a family history and of minor anomalies of the pa late; he considered it a disorder of cortical development and the onse t of psychotic symptoms due to maturation during adolescence ''of cert ain parts of the brain which had lain dormant before''. Clouston's ide a was subsequently eclipsed by the broader dementia-praecox espoused b y Kraepelin and Bleuler, but recent epidemiological, neuroimaging, and neuropathological research supports the existence, within the schizop hrenia syndrome of a group of patients with a severe, early onset, dev elopmental psychosis. This disorder, re-christened as neurodevelopment al schizophrenia, is associated with childhood language and speech dif ficulties which render subjects more likely to later misinterpret thei r own inner speech as external voices; Like all developmental disorder s of language, it is commoner in males. Predisposing factors include t he inheritance of abnormal cerebral asymmetry, and early environmental hazards of brain development such as prenatal exposure to maternal vi ral infection and perinatal complications.