THE DYSPLASTIC NET HYPOTHESIS - AN INTEGRATION OF DEVELOPMENTAL AND DYSCONNECTIVITY THEORIES OF SCHIZOPHRENIA

Two separate theories that attempt to explain different aspects of sch izophrenia have recently attracted much attention. The first, the neur odevelopmental hypothesis, postulates that deviations in early develop ment establish a neuronal phenotype that predisposes to, or, in some v ersions, determines the later onset of schizophrenia. The second theor y proposes that schizophrenic symptoms arise from abnormalities in neu ronal connectivity. Here, we suggest that the findings from these two separate lines of inquiry can be integrated into a unitary framework: the dysplastic net hypothesis. In essence, this proposes that anatomic al and physiological dysconnectivity of the adult schizophrenic brain is determined by dysplastic fetal brain development. We also indicate how abnormal connectivity between brain regions constituting large-sca le neurocognitive networks is expressed in both the prepsychotic and p sychotic phases of schizophrenia, and we examine possible risk factors (genetic and environmental) for dysplastic formation of these network s. (C) 1997 Elsevier Science B.V.