The risk of suffering depression increases 41% in smokers, in comparison with non-smokers. This was the conclusion of a study undertaken with 8,556 participants by scientists of the University of Navarra, in collaboration with the University of Las Palmas de Gran Canaria and the Harvard School of Public Health (USA), and which demonstrates in a pioneering way the direct relationship between tobacco use and this disease. The article, whose first author is Prof. Almudena Sánchez-Villegas, is based on research undertaken over the course of 6 years on university graduates with an average age of 42. "Over the course of the tracking and data collection stage, 190 smokers who initially did not present depression were diagnosed with this disease by a doctor. In addition, 65 who were not diagnosed indicated that they were taking antidepressants during this period,” indicated Miguel Ángel Martínez-González, director of the research project and Chair Professor of the Department of Preventive Medicine and Public Health. Among the mechanisms that shed light on this relationship, he points to “genetic and/or environmental disposition, which will increase the probability that the tobacco habit is retained and that the user will suffer depression as an independent issue.” In addition, the article indicates that those who had given up tobacco more than a decade previously have a lesser probability of developing depression than those who have never smoked. In addition, the researchers noted that an increase in tobacco use was correlated with a lessening of physical activity in the smoker’s free time.