International multicenter studies on psychogenic nonepileptic seizures: A systematic review

The aim of the current paper is to systematically review the literature on the existing international multicenter studies on various aspects of PNES and to highlight their findings and significance. I searched the electronic database PubMed for articles that included any of these search terms: Non-epileptic seizures, Nonepileptic seizures, Pseudoseizures, Non-epileptic events, Nonepileptic events, Dissociative seizures, Psychogenic, PNES, AND "international" or "multicenter" or "cross cultural", in their abstracts and titles and published before August 6, 2019. I searched PsycINFO database (keywords in the abstracts) and also included some of the references of the selected articles if they were relevant. I could identify 12 related manuscripts through the search strategy. These included seven studies on patients with PNES, two surveys, and three consensus group reports. This systematic review showed that international and cross-cultural studies on PNES to date are very limited in number and quality. However, these limited studies have resulted in intriguing observations and conclusions. International and cross-cultural studies may make important contributions to our understanding of different aspects of PNES across borders.