Abstract
BACKGROUND: Depression and anxiety are common among people with multiple sclerosis (MS), as are adverse health behaviours, but the associations between these factors are unclear. OBJECTIVE: To evaluate the associations between cigarette smoking, alcohol use, and depression and anxiety in MS in a cross-Canada prospective study. METHODS: From July 2010 to March 2011 we recruited consecutive MS patients from four MS clinics. At three visits over two years, clinical and demographic information was collected, and participants completed questionnaires regarding health behaviours and mental health. RESULTS: Of 949 participants, 75.2% were women, with a mean age of 48.6 years; most had a relapsing-remitting course (72.4%). Alcohol dependence was associated with increased odds of anxiety (OR: 1.84; 95% CI: 1.32-2.58) and depression (OR: 1.53; 95% CI: 1.05-2.23) adjusting for age, sex, Expanded Disability Status Scale (EDSS), and smoking status. Smoking was associated with increased odds of anxiety (OR: 1.29; 95% CI: 1.02-1.63) and depression (OR: 1.37; 95% CI: 1.04-1.78) adjusting for age, sex, EDSS, and alcohol dependence. Alcohol dependence was associated with an increased incidence of depression but not anxiety. Depression was associated with an increased incidence of alcohol dependence. CONCLUSION: Alcohol dependence and smoking were associated with anxiety and depression. Awareness of the effects of adverse health behaviours on mental health in MS might help target counselling and support for those 'at risk'.