Executive dysfunction in first-episode schizophrenia and relationship to duration of untreated psychosis: The West London Study

Abstract

BackgroundMany studies have demonstrated early generalised cognitive impairment in schizophrenia.AimsTo examine executive function in first-episode schizophrenia, characterise the nature of the impairment and specify any relationships with symptoms and duration of untreated psychosis (DUP).MethodPatients (n=136) and normal controls (n=81) were assessed with the Cambridge Automated Neuropsychological Test Battery, National Adult Reading Test IQ, and Scales for the Assessment of Positive and Negative Symptoms.ResultsMemory and executive impairments in patients were independent of IQ level. Spatial working memory was impaired because of inadequate strategy use. On a planning task, patients showed reduced planning times and suboptimal problem-solving. On an attentional set-shifting task, 75% of patients were able to perform an extra-dimensional shift thought to be a core attribute of prefrontal cortex function. Those who failed had significantly longer DUP.ConclusionsPrefrontal cortex function deteriorates at the onset of psychosis and continues to worsen over time.