Cigarette smoking has no pro-cognitive effect in subjects with obsessive-compulsive disorder: A preliminary study

BACKGROUND: The prevalence of cigarette smoking in patients with different psychiatric disorders is higher than that in the general population, which is partly explained by the pro-cognitive effect of smoking on cognitive functions. In subjects with obsessive-compulsive disorder (OCD), the prevalence of smokers is lower than that in other psychiatric disorders. We hypothesized that cigarette smoking does not provide benefits and even worsen cognitive performance in OCD. SUBJECTS AND METHODS: We compared different executive function subdomains in 20 smoking and 20 non-smoking inpatients with OCD. At the beginning of hospitalization, we assessed visuo-spatial working memory, planning and set-shifting abilities (Cambridge Neuropsychological Test Automated Battery), smoking habits (standardized personal interviews), and the severity of obsessive-compulsive symptoms (Dimensional Yale-Brown Obsessive-Compulsive Scale). RESULTS: The performance of smokers and non-smokers did not differ significantly in any cognitive subdomain. The smoking duration was significantly associated with poorer visuo-spatial working memory performance (P=0.001). CONCLUSIONS: Our results showed that cigarette smoking did not provide cognitive enhancement across various executive function subdomains in subjects with OCD. The lack of beneficial cognitive effects of smoking may make these subjects less prone to smoking and may partially explain the lower rate of smokers in OCD compared with other psychiatric conditions.