Aim: Schizophrenia patients present both reduced slow wave sleep (SWS) and shortened rapid eye movement latency (REML) in polysomnographic (PSG) profiles, which have been linked to dopaminergic and muscarinic impairment, respectively. Two main selective attentional systems involve different anatomical structures. The first system is the parietal cortical areas and thalamic areas, which are linked to cholinergic neurotransmission. This is responsible for automatic attention response. The second system is the frontal regions, which are linked to dopaminergic neurotransmission. This is responsible for voluntary control of attentional resources. It was hypothesized that low attentional performance in schizophrenia patients is associated with shortened REML and reduced SWS.
Methods: The PSG profile was correlated with the continuous performance test (CPT) in 15 schizophrenia inpatients under treatment with risperidone. Schizophrenia was diagnosed according to DSM-IV criteria, and clinical symptoms were evaluated on the Brief Psychiatric Rating Scale.
Results: REML was negatively correlated with errors of omission (P < 0.05), reaction time (RT; P < 0.05) and positively correlated with hit rate (HR; P < 0.05). No association was found between SWS and CPT performance.
Conclusions: The significant indicators of CPT represent different attention processes. Errors of omission, which are linked to the problems with automatic attention processing, RT, which represent the speed of automatic processing, and HR, are involved in the integration of autonomic and voluntary attention control. The present results suggest that REML is associated with thalamus-related automatic attention response. Due to study limitations, however, confirmation of these findings in a large-scale controlled study of drug-naïve patients is needed.