Relation of cigarette smoking and mood disorders to cognitive impairment progression

Background: Both depressive disorders and nicotine use are proven and important risk factors of dementia. The purpose of this study was to verify if cigarette smoking and depression symptoms together are disadvantageous for the prognosis in mild cognitive impairment. Material and methods: A total of 43 patients with a diagnosis of mild cognitive impairment were included in the study. ADAS-Cog was performed upon inclusion in the study and again at least 2 years later. Additionally, patients with ≥18 points in MADRS were qualified as depressive. The Fagerström scale for nicotine dependence was administered to smokers. Results: Our study shows a relation between severity of depressive symptoms and further deterioration of cognitive functions according to ADAS-cog scale. Regression analysis revealed that smoking associated with severity of depressive disorders is also correlated with the progression of cognitive impairment. Conclusions: The results of our study are based on a small number of subjects and should be regarded as early findings. Moreover, nicotine dependency should not be regarded as an isolated factor affecting mood disorders and cognitive impairment progression. Further studies on larger groups of patients and using more sensitive methods of cognitive function assessment are needed.