title: Variables associated with co-existing epileptic and psychogenic nonepileptic seizures: a systematic review.
abstract: OBJECTIVE
  Epileptic seizures (ES) have many mimickers, perhaps the most relevant being psychogenic nonepileptic seizures (PNES). The picture is even more challenging when PNES are associated with ES in a given patient. The aim of this research paper was to delineate the demographic, epileptological and psychiatric profile of that specific population.
  
  
  METHODS
  A systematic review was carried out from 2000 to 2015 for articles in English, French, Italian, Spanish and Portuguese in PUBMED and EMBASE. Cohort or case-control studies reporting prospective or retrospective original data comparing patients with co-existing ES and PNES with those who had PNES only and ES only have been included. In retained studies, the presence of PNES was confirmed by video-electroencephalography (V-EEG). Forty-eight abstracts were identified.
  
  
  RESULTS
  Nine studies were retained. Most showed that female gender predominated in both groups with PNES. Patients with co-existing ES and PNES take higher number of antiepileptic drugs (AEDs) than PNES alone. Two studies showed association of concomitant ES and PNES with earlier age of seizure onset. Localizing EEG features and ES type were evaluated in only two studies and their association with either group was inconclusive. Somatoform, conversion or cluster B personality disorders were more frequent in subjects with PNES than with ES.
  
  
  CONCLUSIONS
  Patients with concomitant ES and PNES are highly heterogeneous, challenging differentiation on clinical grounds. A diagnosis of conversion or somatoform, anxiety disorders, and the use of a higher number of AEDs than psychiatric medications may have an association with co-existing ES and PNES. Further studies are warranted to differentiate patients who only have PNES from those with co-existing ES and PNES.
authors.affiliation: Medicine and Health Sciences Post-Graduate Program, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil; Neurology, Hospital São Lucas, PUCRS, Brazil; Porto Alegre Epilepsy Surgery Program Service, Hospital São Lucas, PUCRS, Brazil. Electronic address: gisbaroni@gmail.com.
authors.forename: Gislaine
authors.initials: G
authors.lastname: Baroni
authors.affiliation: Neurology, Hospital São Lucas, PUCRS, Brazil; Porto Alegre Epilepsy Surgery Program Service, Hospital São Lucas, PUCRS, Brazil. Electronic address: vitoria.piccinini@gmail.com.
authors.forename: Vitoria
authors.initials: V
authors.lastname: Piccinini
authors.affiliation: Neurology, Hospital São Lucas, PUCRS, Brazil; Porto Alegre Epilepsy Surgery Program Service, Hospital São Lucas, PUCRS, Brazil. Electronic address: walvesm.br@gmail.com.
authors.forename: William Alves
authors.initials: WA
authors.lastname: Martins
authors.affiliation: Epilepsy and Electroencephalography (EEG) Service, Hospital de Clínicas, Federal University of Paraná, Brazil. Electronic address: luciano.depaola@gmail.com.
authors.forename: Luciano
authors.initials: L
authors.lastname: de Paola
authors.affiliation: Neurosurgery Hospital São Lucas, PUCRS, Brazil; Porto Alegre Epilepsy Surgery Program Service, Hospital São Lucas, PUCRS, Brazil; Surgery Department, Medical School, PUCRS, Brazil. Electronic address: epaglioli@hotmail.com.
authors.forename: Eliseu
authors.initials: E
authors.lastname: Paglioli
authors.affiliation: Post-Graduate Program in Psychiatry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil. Electronic address: reginamargis@gmail.com.
authors.forename: Regina
authors.initials: R
authors.lastname: Margis
authors.affiliation: Medicine and Health Sciences Post-Graduate Program, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre, Brazil; Neurology, Hospital São Lucas, PUCRS, Brazil; Porto Alegre Epilepsy Surgery Program Service, Hospital São Lucas, PUCRS, Brazil; Internal Medicine Department, Medical School, PUCRS, Brazil. Electronic address: apalmini@uol.com.br.
authors.forename: André
authors.initials: A
authors.lastname: Palmini
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use*; D001008:Anxiety Disorders / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D003937:Diagnosis, Differential; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D006801:Humans; D016896:Treatment Outcome
chemical_list: D000927:Anticonvulsants
keywords: Associated variables; Differential diagnosis; Epileptic seizures; Psychiatric comorbidities; Psychogenic nonepileptic seizures; Somatoform disorders