Cognitive deficits are increasingly recognized as key features of schizophrenia, important determinants of poor psychosocial outcome and targets for treatment strategies. The huge literature on the topic made it clear that cognitive impairment is present in the majority of subjects with schizophrenia, is not an epiphenomenon of symptoms, is a risk factor for psychotic disorders and seems to contribute to poor functional outcome more than symptoms. However, relationships of cognitive impairment with symptoms, drug treatment and duration of untreated psychosis remain controversial and studies involving large cohorts of first episode schizophrenia patients are highly needed to address these topics adequately. The European First Episode Schizophrenia Trial collected demographic, clinical, psychosocial and cognitive baseline data in 498 first episode patients with schizophrenia, schizophreniform or schizoaffective disorder, with minimal or no prior exposure to antipsychotics, and in 220 healthy subjects, comparable with patients for age, sex, race and education level of parents. Z scores of the examined cognitive abilities (number of standard deviations below the comparison group means) ranged from -0.88 to -1.73. No association was found between the duration of untreated psychosis and cognitive impairment. Psychopathological dimensions were weakly correlated with cognitive impairment both at baseline evaluation and after six months of treatment.

According to EUFEST findings, cognitive impairment in patients with first-episode schizophrenia is moderate/severe, has no association with the duration of untreated psychosis, involves several domains of cognition, and is largely independent from psychopathology.