Psychiatric co-morbidity is highly prevalent in idiopathic cervical dystonia and significantly influences health-related quality of life: Results of a controlled study M. Smit a , A. Kuiper a , V. Han b, c , V.C.R. Jiawan d , G. Douma e , B. van Harten f , J.M.T.H. Oen g , M.E. Pouwels h , H.J.G. Dieks i , A.L. Bartels a, j, * , M.A. Tijssen a a University of Groningen, University Medical Center Groningen, Department of Neurology, PO Box 30.001, 9700 RB Groningen, The Netherlands b Department of Neurology, Safarik University, Hlavna 83/81, 04001 Kosice, Slovakia c Department of Neurology, University Hospital L. Pasteur, Kosice, Slovakia d University of Groningen, University Medical Center Groningen, Department of Psychiatry, PO Box 30.001, 9700 RB Groningen, The Netherlands e Martini Hospital, Department of Neurology, PO Box 30.033, 9700 RM Groningen, The Netherlands f Medical Center Leeuwarden, Department of Neurology, PO Box 888, 8901 BR Leeuwarden, The Netherlands g Antonius Hospital, Department of Neurology, PO Box 20.000, 8600 BA Sneek, The Netherlands h Scheper Hospital, Department of Neurology, PO Box 30.002, 7800 RA Emmen, The Netherlands i R€ opcke-Zweers Hospital, Department of Neurology, PO Box 1, 7770 AA Hardenberg, The Netherlands j Ommelander Hospital Group, Department of Neurology, PO Box 30.000, 9930 RA Delfzijl, The Netherlands article info Article history: Received 7 January 2016 Received in revised form 17 May 2016 Accepted 7 June 2016 Keywords: Dystonia Non-motor Psychiatry Health-related quality of life abstract Introduction: The aim of this study was to systematically investigate the prevalence of psychiatric dis- orders and factors influencing health-related quality of life (HR-QoL) in cervical dystonia (CD) patients, in the context of objective dystonia motor severity. Methods: We studied 50 CD patients and 50 matched healthy controls. Psychiatric assessment included the MINIePLUS interview and quantitative questionnaires. Dystonia motor severity (based on video evaluation), pain and disability were determined with the TWSTRS rating scale. In addition, severity of tremor and jerks was evaluated with the 7-point CGI-S scale. HR-QoL was determined with the RAND-36 item Health Survey and predictors of HR-QoL were assessed using multiple regression analysis. Results: In CD patients, the MINI-PLUS revealed a significantly higher prevalence of psychiatric disorders (64% vs. 28%, p ¼ 0.001), with substantially more depression (32% vs. 14%) and anxiety disorders (42% vs. 8%). This was confirmed by the quantitative rating scales. Disease characteristics did not differ between patients with and without a psychiatric diagnosis. HR-QoL in dystonia patients was significantly lowered. The most important predictors of HR-QoL appeared severity of depressive symptoms, pain and disability, but not severity of motor symptoms. Conclusion: Psychiatric co-morbidity is highly prevalent and is an important predictor of HR-QoL in CD patients, rather than dystonia motor severity. Our findings support the theory of a shared neurobiology for motor and non-motor features and highlight the need for systematic research into psychiatric dis- orders in dystonia. Adequate treatment of psychiatric symptoms could significantly contribute to better overall quality of life of CD patients. © 2016 Elsevier Ltd. All rights reserved. 1. Introduction Cervical dystonia (CD) is a hyperkinetic movement disorder characterized by sustained or intermittent contractions of the cer- vical musculature, leading to abnormal head postures. It is the most common form of adult-onset focal dystonia, with a prevalence ranging between 28 and 183 cases per million people [1]. * Corresponding author. Department of Neurology, University Medical Center Groningen, Hanzeplein 1, 9700 RB Groningen, The Netherlands. E-mail addresses: m.smit03@umcg.nl (M. Smit), a.kuiper@umcg.nl (A. Kuiper), vladimir.han@gmail.com (V. Han), v.c.r.jiawan@umcg.nl (V.C.R. Jiawan), g.douma@ mzh.nl (G. Douma), barbera.van.harten@znb.nl (B. van Harten), j.oen@antonius- sneek.nl (J.M.T.H. Oen), e.pouwels@treant.nl (M.E. Pouwels), h.dieks@sxb.nl (H.J.G. Dieks), a.l.bartels@umcg.nl (A.L. Bartels), m.a.j.de.koning-tijssen@umcg.nl (M.A. Tijssen). Contents lists available at ScienceDirect Parkinsonism and Related Disorders journal homepage: www.elsevier.com/locate/parkreldis http://dx.doi.org/10.1016/j.parkreldis.2016.06.004 1353-8020/© 2016 Elsevier Ltd. All rights reserved. Parkinsonism and Related Disorders xxx (2016) 1e6 Please cite this article in press as: M. Smit, et al., Psychiatric co-morbidity is highly prevalent in idiopathic cervical dystonia and significantly influences health-related quality of life: Results of a controlled study, Parkinsonism and Related Disorders (2016), http://dx.doi.org/10.1016/ j.parkreldis.2016.06.004