There are no commercial or financial conflicts of interest directly related to this article. We declare the following interests that are outside of the scope of this article. In the previous 5 years, MJ's employer has received income for expert consultancy activities from GlaxoSmithKline, TENSCare, and LifeCare Ltd. that lie outside of the submitted work. MJ declares book royalties from Oxford University Press. SF discloses Grant/Research/Clinical Trial Support to the University of California. He also receives royalties for books from: Elsevier Publisher [Royalties—pain and pain management]; Oxford University Press [Royalties—pain and pain management]; Wolters Kluwer Publisher [Royalties—pain and pain management] as well as for editorial work for UpToDate/Wolters Kluwer Publisher [chronic pain]. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.