Age at onset and cognitive functioning in schizophrenia.

BACKGROUND Impairments in cognitive functioning are common in schizophrenia, and the degree of impairment may be associated with the individual's age at onset of the disorder. AIMS To examine the effect of age at onset on cognitive functioning using the California Verbal Learning Test, sub-tests from the Wechsler Memory Scale-Revised and sub-scales from the Wechsler Adult Intelligence Scale-Revised among families with schizophrenia. METHOD The effect of age at onset on cognitive function in 237 people with schizophrenia from a population-based sample was examined using linear mixed effects models with family as the random effect, and age, gender, chronicity of the illness and number of affected first-degree relatives as fixed effects. RESULTS Impairment in verbal learning and memory was associated with earlier disease onset. No association was found for working memory or IQ. CONCLUSIONS In patients with early-onset schizophrenia, verbal memory functions in particular should be taken into account in neuropsychological evaluation and efforts at remediation.