Factors associated with tobacco consumption in patients with depression

Smoking and depression are related in a bidirectional way: smoking is the primary avoidable cause of illness and death in patients with depression, and depression is one of the most consistent risk factors for smoking. The main objective of this study is to investigate the relationship between smoking and depression, analyzing sociodemographic and clinical variables such as severity of symptoms, subtype of affective disorder, and its impact on suicidal behavior in the clinical population.A sample of 201 patients, over 18 years of age [mean age (SD) = 53.76 (10.36) years; women = 132 (65.7%)], with a history of depressive episode (unipolar or bipolar) or dysthymia (ICD 10 criteria) was studied.Current smoking prevalence was 43.2% and life-time prevalence 61.2%. No statistically significant differences in smoking prevalence between men and women were found (X2 = 3.896, p = 0.143). The average age of onset was 17.81 (5.60) years. There was a tendency towards a linear association between number of cigarettes/day consumed and severity of depression according to the Hamilton Depression Scale (HDRS) in current smokers (Pearson's R = 0.298, p = 0.050). Multinomial logistic regression analysis showed that current tobacco consumption was associated with higher HDRS scores, with each additional point on the HDRS increasing the likelihood of smoking by 0.062 [p = 0.032; OR (95% CI) = 1.064 (1.005-1.125)].Our results showed that depressed patients present higher prevalence of current smoking than the general population, also suggesting a relationship between severity of consumption and severity of depressive symptoms.