ABNORMALITIES OF BRAIN STRUCTURE AND FUNCTION IN SCHIZOPHRENIA - IMPLICATIONS FOR ETIOLOGY AND PATHOPHYSIOLOGY

In vivo imaging and post-mortem neuropathology studies have detected a variety of abnormalities in brain function and structure in patients with schizophrenia. Current models of the neural mechanisms involved f ocus primarily on frontal and medial temporal lobe structures and thei r interconnections, because deficits in these systems are relatively p rominent against a background of generalized cerebral dysfunction, and because individuals with acquired lesions in these areas show many of the symptoms characteristic of schizophrenia. Family and twin studies have demonstrated similar abnormalities in some of the unaffected bio logical relatives of schizophrenics, indicating that some of these neu ropathological changes are mediated in part by genetic predisposition to the disorder, Further, obstetric complications are associated with an increased risk for phenotypic schizophrenia and with greater severi ty of its neuropathological features in individuals at elevated geneti c risk. These latter findings, combined with evidence of heterotopic d isplacement of neurones in temporolimbic and frontal regions and evide nce that cognitive dysfunction during childhood precedes schizophrenia , imply that at least some of these brain abnormalities are neurodevel opmental in origin, The view emerging from this work is that schizophr enia is a brain disease the neuropathological features of which result at least in part from the unique and interacting influences of geneti c factors and adverse obstetric events in utero.