Effects of cigarette smoking on cognitive deficits in first-episode psychosis

Abstract

Cognitive deficits have been consistently described in psychosis and have been proposed as endophenotype markers. Nicotine administration can improve attentional and working memory deficits in schizophrenia. Compared to the general population, smoking is specially prevalent in schizophrenia.

Aims:

To describe possible differences in cognitive performance in smoking versus non-smoking patients with first-episode psychosis and to determine the presence of smoking-related cognitive enhancement.

Methods:

Sixty-two patients with first-episode psychosis were assessed with a neuropsychological battery that included computerized measurements of attention, working memory, and executive functioning. Patients were grouped into two categories: non-smokers (0 cigarettes/day; n=31) and smokers (20 or more cigarettes/day; n=31).

Results:

Groups were paired for sociodemographic and clinical data. In the sustained attention task, smokers exhibited shorter reaction times than non-smokers (p=0.026) and presented a significantly lower % of omissions (p=0.046). No differences were found in the % of commissions. Similarly, in the working memory task, smokers exhibited shorter reaction times than non-smokers (p=0.020) and presented a significantly lower % of omissions (p=0.002), with no differences in the % of commissions. Compared to non-smokers, smokers needed significantly less time to complete the Stroop interference task (p=0.013) with no significant differences in the % of correct responses. No differences were detected between groups in the Wisconsin Card Sorting Test.

Conclusions:

Cigarette smoking is associated with less marked attentional and working memory deficits in first-episode psychosis and may constitute a self-medication behavior for remediation of neuropsychological dysfunction. This may be relevant for developing new pharmacotherapies for cognitive deficits in psychosis.