Cognitive rehabilitation in schizophrenia: strategies to improve cognition

By first grade, children in whom schizophrenia develops are already performing at nearly a full grade equivalent below their peers.5 There appears to be a period of further cognitive decline (or rather, failure to make ageappropriate gains) between the ages of 12 and 17-several years before the first psychotic episode.5,6,9 After the first episode, and the patient has stabilized clinically, the cognitive deficits remain fairly stable.10-12 At that point, scores of global cognition range from between 1 and 2 standard deviations below those of healthy cohorts.13,14 While all domains of cognition are affected in schizophrenia, there are selective areas of increased impairment- particularly verbal and visuospatial memory, attention, executive function, and speed of processing (Table 1).15-20 Verbal memory impairments are the most robust and the most profound.10,14-16,18 Impairments in cognition are not related to illness state and are present and stable even during periods of positivesymptom remission. [...] positive symptoms and cognitive deficits are only negligibly correlated.21 However, negative and disorganization symptoms show modest correlations with cognition.21,22 Functional consequences of cognitive deficits Relative to the positive, negative, and disorganization symptom domains, cognition is the strongest predictor of functional outcome.1,2 Cognitive deficits in schizophrenia have been shown to interfere with various aspects of daily functioning, including employment, independent living, and quality of life.23-26 In 2 literature reviews, Green and colleagues1,2 demonstrated that 4 specific neurocognitive domains were significantly associated with functional outcomes: executive functioning, immediate verbal memory, secondary verbal memory, and vigilance.