Chronic tobacco smoking and neuropsychological impairments: A systematic review and meta-analysis.

The link between neuropsychological impairments and chronic tobacco smoking is not clear and in the current literature there is a lack of robust analyses investigating this association. A systematic review of the literature was conducted in order to identify relevant longitudinal and cross-sectional studies conducted from 1946 to 2017. A meta-analysis was performed from 24 studies testing the performance of chronic tobacco smokers compared with non-smokers on neuropsychological tests related to eight different neuropsychological domains. The results revealed a cross-sectional association between neuropsychological impairments and chronic tobacco smoking in cognitive impulsivity, non-planning impulsivity, attention, intelligence, short term memory, long term memory, and cognitive flexibility, with the largest effect size being related to cognitive impulsivity (SDM = 0.881, p <0.005), and the smallest effect size being related to intelligence (SDM = 0.164, p < 0.05) according to Cohen's benchmark criteria. No association was found between chronic smoking and motor impulsivity (SDM = 0.105, p = 0.248). Future research is needed to investigate further this association by focusing on better methodologies and alternative methods for nicotine administration.