History of violence/maltreatment and psychogenic non-epileptic seizures

Purpose To study the association of earlier violence/maltreatment with the occurrence of PNES in a nationwide population sample. Methods This is a nested case-control study performed using Swedish nationwide registers. Cases were all individuals born in Sweden between 1941 and 2009 with incident PNES between 2001 and 2013 while resident in Sweden according to the Swedish Patient Register. For each case, 10 controls, alive and PNES-free at time of PNES diagnosis of the matched case, were randomly selected from the Swedish Total Population Register, matched on age and sex. To test the specificity of the association, we conducted two similar analyses for epilepsy and dissociative disorder with motor symptoms or deficit, as comparators to PNES. Registers were examined in search of all coded diagnoses of child maltreatment or violence episodes before the index date among the cases and controls. Results 885 patients received a first diagnosis of PNES. 7.6 % of cases had a history of violence/maltreatment, compared to 1.1 % of controls, giving a crude OR of 7.9 (95 % CI: 3.7–11.0). The ORs decreased but remained significant after adjustment for socio-economic factors (OR = 6.3, 95 % CI: 4.4–9.0) and psychiatric comorbidities (OR = 5.2, 95 % CI: 3.5–7.9). The association was also evident for epilepsy and dissociative disorder, although of lower magnitude. Conclusion Patients with PNES have a history of violence/maltreatment more frequently than the rest of the population. This association can be influenced by socio-economic factors and the presence of concurrent psychiatric disturbances.