Similarities in cognitive impairment between recentonset and chronic schizophrenia patients: a consideration for the neurodevelopmental hypothesis

Abstract

Impairment in attention, memory, processing speed and executive functions have been described in patients with schizophrenia. Such impairments can be observed in early stages of the disease and in chronic patients; discrepancy in findings regarding the cognitive deficits at different stages of the illness keeps the debate about schizophrenia as a neurodegenerative condition which courses with continuous deterioration, or if deficits remain stable, as the neurodevelopmental hypothesis suggests. The aim of the present study was to compare the cognitive performance of recent-onset (RO) and chronic (CH) schizophrenia patients to contrast the neurodevelopmental hypothesis against the neurodegenerative approach.

Methods. Twenty RO participants (< 5 years from first psychotic episode) and 30 CH patients (> 5 years from first psychotic episode) were included in the sample. The MATRICS Consensus Cognitive Battery (MCCB), Tower of London test (ToL), Wisconsin Card Sorting Test (WCST) and Stroop Test were used for cognitive evaluation. ANCOVA analysis was performed for group comparisons.

Results. No differences between RO and CH patients were identified on most cognitive tests. However, a significant difference was observed in the visual spatial span test from MCCB.

Conclusions. We conclude that cognitive deficits remain stable over the course of the disease. Our findings are consistent with the neurodevelopmental hypothesis of schizophrenia rather than the neurodegenerative approach.