Schizophrenia, smoking status, and performance on the matrics Cognitive Consensus Battery.

Abstract

Cognitive deficits and high rates of nicotine dependence are consistently documented in the schizophrenia literature. However, there is currently no consensus about how regular smoking influences cognition in schizophrenia or which cognitive domains are most affected by chronic smoking. Previous studies have also failed to disambiguate the effects of chronic nicotine from those of acute exposure. The current study uses a novel approach to testing nicotine addicted patients at a time-point between acute enhancement and withdrawal and implements the MATRICS Cognitive Consensus Battery (MCCB) to compare the overall cognitive performance of regular smokers (n=40) and nonsmokers (n=36) with schizophrenia. Controlling for age, gender, and education, smokers with schizophrenia were significantly more impaired on a visual learning task, the Brief Visuospatial Memory Test-Revised (BVMT-R), than their nonsmoking peers. Among smokers, smoking behavior (i.e., exhaled carbon monoxide levels of smokers) predicted BVMT-R T score; greater smoking was associated with more impaired visual learning. Negative symptom severity was not predictive of greater visual learning deficits in smokers or nonsmokers. Future longitudinal research will be required to determine if there is a dose-response relationship between chronic nicotine and visual learning impairment in patients at various stages of psychotic illness.