The largely consistent columnar circuitry observed throughout the cortex may serve to continuously predict bottom-up activation based on invariant memories. This "memory-prediction" function is essential to efficient and accurate perception. Many of the defined cognitive deficits associated with schizophrenia suggest a breakdown of memory-prediction function. As deficits in memory-prediction function are proposed to lie more proximal to the biological causes of schizophrenia than deficits in standard cognitive constructs, tests that more directly probe memory-prediction function may be especially sensitive predictors of conversion in individuals at high-risk for schizophrenia. In this article, we review the conceptual basis for this hypothesis, and outline how it may be tested with specific cognitive paradigms. The accurate identification of cognitive processes that precede the onset of psychosis will not only be useful for clinicians to predict which young people are at greatest risk for schizophrenia, but will also help determine the neurobiology of psychosis onset, thus leading to new and effective treatments for preventing schizophrenia and other psychoses.
Cognition Disorders ; Humans ; Memory ; Neuropsychological Tests ; Predictive Value of Tests ; Risk Assessment ; Schizophrenia ; etiology ; physiopathology ; Schizophrenic Psychology

AIMVarious forms of social adversity have been implicated in the development and emergence of psychosis. However, how and when these events exert their influences are not clear. In this paper, we attempt to examine these putative psychosocial factors and place them in a temporal context and propose a neurobiological mechanism linking these factors.

METHODSMedline databases were searched between 1966 and 2007 followed by the cross-checking of references using the following keywords: psychosocial, stress, stressors, life events, psychological, combined with psychosis and schizophrenia.

RESULTSWhile some findings are conflicting, there are a number of positive studies which suggest that factors like prenatal stress, urban birth and childhood trauma accentuate the vulnerability for schizophrenia and other psychoses while other factors like life events, migration particularly being a minority group, and high expressed emotions, which occur later in the vulnerable individual may move the individual towards the tipping point for psychosis.

CONCLUSIONOverall, there is evidence to implicate psychosocial factors in the pathophysiology of schizophrenia. These factors may act via a common pathway, which involves stress-induced dysregulation of the HPA axis and the dopaminergic systems. To establish the causal relationship of the various factors would require prospective studies that are adequately powered.

Humans ; Nervous System ; physiopathology ; Psychology ; Schizophrenia ; physiopathology