Neurocognition in schizophrenia: from prodrome to multi-episode illness

Individuals with schizophrenia present a neuropsychological deficit throughout the course of the disorder. Few studies have addressed the progression of the deficit since the prodromal phase of the disorder. This investigation explored neurocognition in accordance with the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus recommendations. The aim of the study was to explore the presence of neurocognitive impairment in ultra-high-risk individuals and the stage of this impairment in samples at different phases of illness. Thirty-six individuals with a prodromal syndrome, 53 first-episode and 44 multi-episode schizophrenia patients were assessed to examine neuropsychological performance. ANCOVA analysis adjusted for possible confounder factors and planned contrasts with healthy controls were undertaken. The results revealed deficits in speed-of-processing, visual-learning and social-cognition in prodromal individuals, and of all other neuropsychological domains in both first-episode and multi-episode patients. Furthermore impairment was found in the first-episode and in the multi-episode group, respectively on working-memory and attention. Within the framework of the neurodevelopmental model of schizophrenia, our results suggest the presence of neuropsychological impairment before the onset of full-blown psychosis. Moreover, the deficits are larger in the more chronic groups, according to the theory of an ongoing neurodevelopmental alteration.