Published Online: June 17, 2013. doi:10.1001/jamainternmed.2013.6705.
Study concept and design: Kessner, Wiech, Bingel.
Acquisition of data: Kessner.
Analysis and interpretation of data: All authors.
Drafting of the manuscript: Kessner, Wiech, Ploner, Bingel.
Critical revision of the manuscript for important intellectual content: Wiech, Forkmann, Bingel.
Statistical analysis: All authors.
Obtained funding: Bingel.
Administrative, technical, and material support: Bingel.
Study supervision: Wiech, Bingel.
Conflict of Interest Disclosures: None reported.
Funding/Support: This work was supported by grants from the German Research Foundation (BI 789/2-1) and the German Federal Ministry of Education and Research (01GQ0808).
Additional Contributions: Christoph Ritter, MS, Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, helped with the data analysis.