Prescription rates of methylphenidate (MPH) are sharply rising in most Western countries. Although it has been reported that MPH has abuse potential, little is known about the prevalence of intravenous (IV) abuse of MPH. The aim of the study was to investigate the prevalence of IV MPH abuse among treatment-seeking IV substance abusers in Iceland.
This is a descriptive population-based study using a semistructured interview assessing sociodemographics, substance abuse history, and the method of administration of 108 IV substance abusers. During 1 year, consecutively admitted adult inpatients with substance use disorder at any detoxification center in Iceland that reported any IV substance abuse in the past 30 days were invited to participate. Abuse was defined as nontherapeutic use of a substance to gain psychological or physiological effect.
Prevalence of any IV MPH abuse among participants was 88% in the last 30 days (95% confidence interval [CI], 0.82-0.94) and MPH was the most commonly abused substance (65%) and the preferred substance (63%). Around one third (30%) reported MPH as the first IV substance ever abused. However, among those reporting a shorter history than 10 years of IV abuse, 42% reported MPH as the first IV substance ever abused.
This first nationwide study on IV abuse of MPH shows that it is common among treatment-seeking IV abusers in Iceland and suggests that MPH has high abuse potential. Therefore, both the use and possible abuse of MPH in those with high abuse potential should be monitored, especially in countries where MPH prescriptions rates are on the rise.
From the Mental Health Services, Landspitali—the National University Hospital (GDB, HMH, BOR, ES, HB), Reykjavik, Iceland; Centre for Ethics, Law and Mental Health (SS), Institute of Neuroscience and Physiology, The Sahlgrenska Academy, The University of Gothenburg, Gothenburg, Sweden; School of Health Sciences (GDB, HMH, BOR, ES, AM), Faculty of Medicine, University of Iceland, Reykjavík, Iceland; and Department of Pharmacology and Toxicology (MJ), Faculty of Medicine, University of Iceland, Reykjavik, Iceland.
Send correspondence and reprint requests to Gudrun D. Bjarnadottir, MD, Mental Health Services, Landspitali—the National University Hospital, 101 Reykjavik, Iceland. E-mail: email@example.com.
None of the authors have competing interests. G.D. Bjarnadottir did parts of this research during 4 months' leave from her clinical duties at Landspitali University Hospital. This study was conducted without any influence from the Hospital or other organizations. G. D. Bjarnadottir received a travel grant from the Nordic Psychiatric Association in June 2012. No other relationships or activities that could appear to have influenced the submitted work.
Author contribution: Bjarnadottir, Magnusson, Haraldsson, Steingrimsson, and Rafnar designed the study. Bjarnadottir and Bragadottir acquired the data. Bjarnadottir, Haraldsson, Rafnar, Steingrimsson, Sigurdsson, and Magnusson drafted the paper. Bjarnadottir, Magnusson, Haraldsson, Rafnar, Sigurdsson, Johannsson, and Steingrimsson take the responsibility for the integrity of the data and the accuracy of the data analysis. All authors have read and understand the Instructions for Authors. Bjarnadottir, Haraldsson, and Magnusson are guarantors and affirm that the manuscript is honest, accurate, and transparent and no important aspects of the study have been omitted and all discrepancies have been explained. All authors had access to the data, interpreted the data, critically revised the draft for important intellectual content, and gave final approval of the manuscript to be published. Bjarnadottir presented preliminary results at the European Psychiatry Congress in Nice, 2013.
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Received July 16, 2014
Accepted January 10, 2015