Psychiatric Diagnoses, Medication and Risk for Disability Pension in Multiple Sclerosis Patients; a Population- Based Register Study Philip Brenner 1 *, Kristina Alexanderson 2 , Charlotte Bjo ¨ rkenstam 2 , Jan Hillert 3 , Jussi Jokinen 1 , Ellenor Mittendorfer-Rutz 2 , Petter Tingho ¨g 2 1 Division of Psychiatry, Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden, 2 Division of Insurance Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden, 3 Division of Neuro, Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden Abstract Background: Psychiatric comorbidity is common among multiple sclerosis (MS) patients. The majority of MS patients of working ages are on disability pension. The aims of this study were to chart the prevalences of psychiatric diagnoses and medications among MS patients of working ages, and to investigate their association with the risk for future disability pension. Methods: This nationwide, population-based prospective cohort study includes 10,750 MS patients and 5,553,141 non-MS individuals who in 2005 were aged 17–64 years. Psychiatric diagnoses and medications were identified using nationwide registers. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated adjusting for socio-demographics. Furthermore, a survival analysis with five-year follow-up was performed among the 4,571 MS patients not on disability pension in 2005, with psychiatric diagnoses and medication as risk factors, and disability pension as the outcome. Results: Among MS patients, 35% had been prescribed psychiatric medication compared to 10% of non-MS individuals, adjusted OR 3.72 (95% CI 3.57 to 3.88). Ten percent of MS patients had received a psychiatric diagnosis, compared to 5.7% of non-MS individuals, OR 1.82 (95% CI 1.71 to 1.94). Serotonin reuptake inhibitors (SSRIs), were the most commonly prescribed drugs (17%) among MS patients, while depression (4.8%) was the most common psychiatric diagnosis. In the survival analysis, MS patients with any psychiatric diagnosis had a hazard ratio (HR) of 1.83 (95% CI 1.53 to 2.18) for disability pension compared to other MS patients. MS patients with any psychiatric drug prescription had a HR for disability pension of 2.09 (95% CI 1.84 to 2.33). Conclusion: Psychiatric diagnoses and medications are common among MS patients and adversely affect risk for disability pension. This highlights the importance of correct diagnosis and management of psychiatric comorbidity, in a clinical as well as in a societal perspective. Citation: Brenner P, Alexanderson K, Bjo ¨ rkenstam C, Hillert J, Jokinen J, et al. (2014) Psychiatric Diagnoses, Medication and Risk for Disability Pension in Multiple Sclerosis Patients; a Population-Based Register Study. PLoS ONE 9(8): e104165. doi:10.1371/journal.pone.0104165 Editor: Sreeram V. Ramagopalan, University of Oxford, United Kingdom Received April 25, 2014; Accepted July 4, 2014; Published August 5, 2014 Copyright: ß 2014 Brenner et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability: The authors confirm that, for approved reasons, some access restrictions apply to the data underlying the findings. According to the Swedish Ethical Review Act, the Personal Data Act, and the Administrative Procedure Act, data can only be made available after legal review for researchers who meet the criteria for access to this type of sensitive and confidential data. If readers want to request the data, they may contact Prof. Kristina Alexanderson, Division of Insurance Medicine, Department of Clinical Neuroscience, Karolinska Institutet, Berzelius va ¨g 3, KI Campus Solna,SE-171 77 Stockholm, Sweden. E-mail: kristina.alexanderson@ki.se. Funding: This study was financially supported by Biogen Idec and the Swedish Council for Working Life and Social Research (grant number 2007-1762). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: Biogen Idec provided funding toward this study. JH has over the years received honoraria for serving on advisory boards for BiogenIdec and Novartis and speaker’s fees from BiogenIdec, Merck-Serono, Bayer-Schering, Teva and Sanofi-Aventis. He has served as P.I. for projects, or received unrestricted research support from, BiogenIdec, Merck-Serono, TEVA, Sanofi-Aventis and Bayer-Schering and is in the process of negotiating a research grant from Novartis. There are no patents, products in development or marketed products to declare. This does not alter adherence to all the PLOS ONE policies on sharing data and materials. * Email: philip.brenner@ki.se Introduction Multiple sclerosis (MS) is a neuroinflammatory disease which can affect all functions of the central nervous system. Various socio-demographic factors are associated with a higher risk for MS, such as female sex [1], place of residence during childhood [2], and low educational level [3]. MS is the most common cause of non-traumatic disability among young and middle-aged adults in the western hemisphere, and as such, leads to high rates of disability and societal costs [4–6]. In a recent study, the rate of MS patients of working ages who were disability pensioned was more than 60% [7], highly elevated compared to in the equivalent general population. PLOS ONE | www.plosone.org 1 August 2014 | Volume 9 | Issue 8 | e104165