Effects of Age and Cognitive Reserve on Cognitive Remediation Therapy Outcome in Patients With Schizophrenia

Abstract

Older people with a diagnosis of schizophrenia seem to show fewer benefits following cognitive remediation therapy (CRT). It is not clear whether cognitive reserve modifies the relationship with age. A total of 134 individuals with schizophrenia were pooled from one randomized control trial and one observational trial. Eighty-five participants received more than 20 sessions of CRT and 49 participants received fewer than 20 sessions of CRT or treatment as usual. Participants were divided into two groups according to their age (younger than 40 years: younger, N = 77; and 40 years or older: older, N = 57). Cognition (working memory, cognitive flexibility, and planning) was assessed at baseline and posttreatment. Premorbid IQ and vocabulary at baseline were used as cognitive reserve proxies. There was a significant effect of CRT on working memory in younger but not older participants. Better premorbid IQ was associated with better working memory performance in younger participants irrespective of treatment. No significant effects of treatment or cognitive reserve were revealed in older participants. Cognitive reserve proxies did not modify CRT treatment effect. In conclusion, the effects of CRT were limited in older people with schizophrenia. Cognitive reserve could not be shown to influence the relationship of age with CRT efficacy. Better premorbid IQ was associated with increased practice effects on working memory in younger but not older individuals.