Adult-onset psychogenic nonepileptic seizures: a multicenter international study

Purpose: The aim of this multi-center international cross-cultural study was to compare clinical variables in a large sample of people with adult-onset psychogenic nonepileptic seizures (PNES).
Methods: In this retrospective study, we evaluated persons with documented PNES, who were older than 16 years of age at the onset, from four countries (i.e., Iran, Brazil, Venezuela, and Argentina) regarding their age, gender, PNES semiology, and possible predisposing factors.
Results: We included 389 patients (244 from Iran, 66 from Brazil, 51 from Venezuela, and 28 from Argentina). Age at diagnosis was 32 ± 9 years (range: 17-64 years) and age at the onset of seizures was 27 ± 8 years (range: 17-49 years). There was a female predominance in all countries. The demographic characteristics and factors associated with PNES were similar among the countries. However, there were significant semiological differences among the countries.
Conclusion: This study corroborates the notion that PNES share more similarities than differences cross-culturally and across international borders. However, the background determined by cultural, ethnic and religious differences may influence the semiology of PNES. Further cross-cultural studies involving more than two continents may advance our understanding of PNES.