[Neurodevelopmental hypothesis of schizophrenia]

Re-assembling the heterogeneic arguments in favour of organic factors (be whether genetic or early environmental exposures), the neuro-developmental hypothesis of schizophrenia proposes that the illness is due to an early insult (pre- or perinatal) that affects the development of the brain, leading to anomalies that express themselves only after the event, once cerebral maturity has been attained. The hypothesis rests on three types of arguments; neuropathological, clinical and epidemiological. We will successively examine the neuropathological observations made in post-mortem studies of the brains of affected patients and the studies in morphological neuro-imagery, then the results of research into aetiological factors, and the data concerning children susceptible to later development of the illness. Finally, we will address the mechanisms proposed to explain why the illness only presents, on average, 20 years after the initial hypothetical insult.