[Transmitter dysfunction in patients with schizophrenia. Significance for cognitive functioning and treatment]

The great diversity of schizophrenic symptoms rules out one simple etiological explanation. However,impairment of information processing, including disruption of sensorimotor gating, is a consistent finding in schizophrenic patients. Dysfunction in sensorimotor gating is believed to be the result of different developmentally or environmentally caused disturbances involving the neural trajectories involved in information processing. Psychopathology and cognition will depend on the primary involvement of distinct parts of these circuits and on secondarily derived time-dependent disturbances of transmitter function. This review is focused on clinical and preclinical evidence for the impact of interactions between glutamatergic, dopaminergic, serotonergic and noradrenergic brain systems on cognitive performance. The hypothetical consequences of transmitter dysfunction for progressive development of impairment in sensorimotor gating are illustrated. Finally, the broad receptor profile of second generation antipsychotics is analysed to explain the clinical improvement in neurocognition that may occur during treatment with such drugs.