Objective

To investigate the hypothesis that patients diagnosed with PNES on video-EEG monitoring (VEM) have increased mortality by comparison to the general population.

Methods

This retrospective cohort study included patients evaluated in VEM units of three tertiary hospitals in Melbourne, Australia, between January 1^st, 1995 and December 31^st, 2015. Diagnosis was based on consensus opinion of experienced epileptologists and neuropsychiatrists at each hospital. Mortality was determined in patients diagnosed with PNES, epilepsy or both conditions, by linkage to the Australian National Death Index (NDI). Lifetime history of psychiatric disorders in PNES was determined from formal neuropsychiatric reports. 

Results

5,508 patients underwent VEM. 674 (12.2%) were diagnosed with PNES, 3064 (55.6%) with epilepsy, 175 (3.2%) with both conditions, and 1,595 (29.0%) received other diagnoses or had no diagnosis made. The standardised mortality ratio (SMR) of patients diagnosed with PNES was 2.5 (95% CI 2.0–3.3). Those younger than 30 years had an 8-fold higher risk of death (95% CI 3.4–19.8). Direct comparison revealed no significant difference in mortality rate between diagnostic groups. Amongst deaths in patients diagnosed with PNES (n=55), external causes contributed 18%, with 20% of deaths in those younger than 50 years attributed to suicide, and “epilepsy” was recorded as the cause of death in 24%. 

Conclusions

Patients diagnosed with PNES have a SMR 2.5 times above the general population, dying at a rate comparable to those with drug-resistant epilepsy. This emphasises the importance of prompt diagnosis, identification of risk factors, and the implementation of appropriate strategies to prevent potential avoidable deaths.