Competing interests: We declare the following conflicts of interest, based on NICE’s policy on conflicts of interests (www.nice.org.uk/Media/Default/About/Who-we-are/Policies-and-procedures/code-of-practice-for-declaring-and-managing-conflicts-of-interest.pdf): GR no declarations; JP no declarations; DD no declarations; PC received support from Britannia Pharmaceutics to attend the European Federation of Neurological Societies (June 2014), and from Bial Pharmaceutics to attend the American Epilepsy Society Meeting (December 2016). All support was within Association of British Pharmaceutical Industry guidelines and was declared under the NICE declaration of interest’s policy. He and his wife have modest shareholdings in a range of pharmaceutical companies, held within ISA funds and managed on their behalf without their involvement in any investment decisions. He is currently principal investigator for a trial of a novel agent for cataplexy, funded by Jazz Pharmaceuticals, and co-investigator for a trial of a treatment for super-refractory status epilepticus, funded by Sage Therapeutics. He is a joint supervisor for a doctoral student at Manchester Heart Centre, funded by Medtronic; he receives no personal financial benefit for any of these roles.