The data were derived from a study evaluating a novel treatment for cognitive function in bipolar disorder. Smoking status was determined by self-report; cognitive function was evaluated with a comprehensive cognitive battery, which included measures of psychomotor speed, attention, memory, learning and executive function. The relations between smoking status and cognitive measures were evaluated with two independent-samples t-test and multiple regression.
The sample comprised forty-three subjects with bipolar disorder (Type I/II). There were no consistent differences in neuropsychological performance between current smokers (N = 16) and non-smokers (N = 27) on most tasks. The occurrence of subjective cognitive failures, as measured with the Cognitive Functioning Questionnaire, was non-significantly lower for smokers compared to non-smokers. Lifetime “smoking load” was negatively associated with premorbid intelligence as estimated by the National Adult Reading Test.
This pilot study provides preliminary evidence that cigarette smoking may exert a salutary effect on subjective, but not objective, measures of cognitive function in euthymic bipolar patients. A larger sample size evaluating this hypothesis would be less vulnerable to type II error.