What have cognitive deficits to do with schizophrenic symptoms?

This paper considers possible relationships between cognitive deficits and symptomatology in schizophrenia. It is argued that a combination of defective filtering and slowness in response selection results in a state of information overload in acute schizophrenia. The methods by which normal subjects adapt to experimenter-induced overload may therefore be relevant to aspects of schizophrenic behaviour. The considerable intra- and inter-subject variability in symptomatology of schizophrenic patients may represent differeing adaptations to similar cognitive disturbance, such secondary abnormalities being prominent in chronic patients. Sections of the literature on acute-chronic differences are consistent with such a formulation, although one cannot infer intra-individual change from cross-sectional studies; there is a clear need for longitudinal investigations in this area. The preferred method of adaptation will be dependent on the severity of overload, the environment, and personality factors independent of the psychosis. The implications for the modification of schizophrenics' behavioural abnormalities by operant procedures are discussed.