Cognition is impaired across the spectrum of schizophrenia, with most impairment occurring by the time of first-episode schizophrenia, researchers in Mexico report. "These findings support a 'one-hit' model, where most of the cognitive deficits occur during the first episode and do not progress even with prolonged durations of untreated psychosis," Dr. Camilo de la Fuente-Sandoval of Instituto Nacional de Neurologia y Neurocirugia, in Mexico City, told Reuters Health by email. Some studies suggest that individuals with schizophrenia experience a progressive decline in cognitive domains during the first decade of their illness, whereas others have proposed that most cognitive deficits are present during the first episode and remain stable thereafter. Dr. de la Fuente-Sandoval and colleagues examined the temporal nature of cognitive deficits in their study of three groups of antipsychotic-naive patients: 87 at clinical high-risk (CHR) for psychosis, 64 with first-episode psychosis (FEP) and 40 with chronic schizophrenia. They also included 102 matched healthy controls. Cognition, as assessed with the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery, was significantly impaired in all patient groups, compared with the control group. Cognitive impairment was significantly greater among patients with FEP or chronic schizophrenia, with no significant difference between those two groups, the researchers report in JAMA Psychiatry. Within the FEP and chronic schizophrenia groups, there were no significant associations between duration of untreated psychosis and any cognitive domain. "Early detection, including the CHR stage, needs to be emphasized," Dr. de la Fuente-Sandoval said. "We need to implement strategies to mitigate the decline in cognitive function between the CHR and FEP stages." —Will Boggs MD Source
