Mortality in patients with psychogenic non-epileptic seizures a population-based cohort study

Objectives: To compare mortality, comorbidities and causes of death in people with psychogenic non-epileptic seizures (PNES), epilepsy and the general population.

Methods: Using linkage of multiple Swedish national registers, we identified individuals with incident diagnosis of PNES, epilepsy and conversion disorder with motor symptoms or deficits, and 10 controls for each. Main outcome was all-cause mortality. Causes of death were categorised into non-natural (eg, suicide, injuries) and natural. Conditional Cox regression models were used to estimate HRs and 95% CIs for mortality. HRs were adjusted for socioeconomic factors and psychiatric comorbidities.

Results: Included were 885 individuals with PNES, 50 663 with epilepsy and 1057 with conversion disorder and motor symptoms or deficits. We found 32 (3.6%) deaths among individuals with PNES, compared with 46 (0.5%) deaths in controls, giving an adjusted HR of 5.5 (95% CI 2.8 to 10.8). Patients with epilepsy had a 6.7 times higher risk of death (95% CI 6.4 to 7.0) compared with individuals without epilepsy. The association between conversion disorder with motor symptoms or deficits was non-significant after adjusting for psychiatric comorbidities. PNES carried a higher risk of natural (HR 8.1, 95% CI 4.0 to 16.4) and non-natural causes of death (HR 15.3, 95% CI 3.0 to 78.6). Suicide ranked high in patients with PNES (18.8%) and conversion disorder with motor symptoms and deficits. The association between PNES diagnosis and all-cause mortality varied with age and time since diagnosis.

Conclusion: Like epilepsy, PNES carries a higher than expected risk of both natural and non-natural causes of death. The high proportion of suicides requires further investigation.