Mortality in patients with psychogenic non-epileptic seizures

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 1st, 1995 and December 31st, 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.