Effects of Tobacco Smoking on Neuropsychological Function in Schizophrenia in Comparison to Other Psychiatric Disorders and Non-psychiatric Controls
Address correspondence to Dr. George, Department of Psychiatry, University of Toronto, Centre for Addiction and Mental Health (CAMH), 250 College Street, CS 734, Toronto, ON, Canada M5T 1R8. E-mail: email@example.com.
Background and Objectives
Compared to the general population cigarette smoking prevalence is elevated in psychiatric disorders such as schizophrenia (SZ), bipolar disorder (BD), and major depressive disorder (MDD). These disorders are also associated with neurocognitive impairments. Cigarette smoking is associated with improved cognition in SZ. The effects of smoking on cognition in BD and MDD are less well studied.
We used a cross-sectional design to study neuropsychological performance in these disorders as a function of smoking status. Subjects (N = 108) were SZ smokers (n = 32), SZ non-smokers (n = 15), BD smokers (n = 10), BD non-smokers (n = 6), MDD smokers (n = 6), MDD non-smokers (n = 10), control smokers (n = 12), and control non-smokers (n = 17). Participants completed a neuropsychological battery; smokers were non-deprived.
SZ subjects performed significantly worse than controls in select domains, while BD and MDD subjects did not differ from controls. Three verbal memory outcomes were improved in SZ smokers compared with non-smokers; smoking status did not alter performance in BD or MDD.
Conclusions and Scientific Significance
These data suggest that smoking is associated with neurocognitive improvements in SZ, but not BD or MDD. Our data may suggest specificity of cigarette-smoking modulation of neurocognitive deficits in SZ. (Am J Addict 2013;22:46-53)