A broad cortical reserve accelerates response to cognitive enhancement therapy in early course schizophrenia

Cognitive rehabilitation can improve cognition in schizophrenia and prevent disability. It is unknown, however, whether a greater neurobiologic reserve, as measured by cortical volumes, will predict a favorable response to rehabilitation. We investigated this question in early course schizophrenia patients treated with Cognitive Enhancement Therapy (CET).

Outpatients in the early course of schizophrenia or schizoaffective disorder were randomly assigned to CET (n=29) or an Enriched Supportive Therapy control (n=21) and treated for two years. Cortical surface area and gray matter volume data were collected before treatment using structural magnetic resonance imaging. Neurocognition and social cognition were assessed before, and after one and two years of treatment. Moderator analyses examined the impact of pre-treatment cortical surface area and gray matter volume on differential neurocognitive and social-cognitive response to CET.

Pre-treatment, whole brain cortical surface area and gray matter volume significantly moderated the effects of CET on social cognition, but not neurocognition. Greater neurobiologic reserve predicted a rapid social-cognitive response to CET in the first year of treatment; patients with less neurobiologic reserve achieved a comparable social-cognitive response by the second year. While nearly every regional measurement significantly contributed to this accelerated social-cognitive treatment response, effects were the strongest in the temporal cortex.

A broad cortical surface area and gray matter reserve is associated with an accelerated social-cognitive response to CET in early schizophrenia, yet the benefits of cognitive rehabilitation are achieved in those with less initial cognitive resources after a longer duration of treatment.