November 3, 2017
Too low a level
of a hormone in the blood which protects against stress may be the cause of
epilepsy-like seizures which doctors had otherwise believed had solely
psychological causes. New research results may help to improve the diagnosis
and treatment of an otherwise mystifying disorder.
In Denmark, as many as 2,000 people — in particular women — suffer from
spasms which are similar to epileptic seizures, but which cannot be measured,
prevented, treated or explained. Until now, as with the publication of a study
from Aarhus University, researchers show that patients with the seizures —
which are known as psychogenic non-epileptic seizures (PNES) in medical
language — have a lower level of the hormone neuropeptide Y (NPY) in their
blood. This is a hormone that is associated with an increased resilience for
dealing with stress. In the study, the same patients have reported a higher
degree of different types of abuse such as sexual abuse, violence, bullying,
feelings of abandonment and the experience of reduced quality of life.
The findings indicate that there is a biological reason for developing
PNES. According to one of the researchers behind the study, associate professor
at the Department of Clinical Medicine, Michael Winterdahl, this is big step
towards improved diagnosis and treatment. He calls the result, just published
in the scientific journal Stress, an important discovery so far for
understanding the seizures, which are categorised under the group of disorders
known as functional disorders.
“In the past, patients were called hysterical women. We stopped
calling patients that a long time ago but the patients are still severely
affected by a disorder that is difficult to understand and describe, both for
the patients themselves and the outside world. And so far, it has not been
possible to identify why people develop these seizures. It just appears to be
an unfortunate combination of various factors which predispose, trigger and
maintain the seizures,” says Michael Winterdahl.
PNES seizures look like epileptic seizures with cramping in the arms and
legs and tossing of the head. A seizure can last from a few seconds to many
hours. Many of the patients have been undergoing epilepsy treatment for years
without other effects than the side effects from the epilepsy medicine.
“It clearly places a terrible strain on both the person affected and
their relatives. Moreover, it is frustrating for the patients to find that
there is not a physiological cause which you can do something about,” says
In the study, the researchers measured the concentration of a wide range of
hormones in the blood of 15 women with PNES and 60 control subjects. In
addition to significantly lower NPY values in the PNES patients compared with
the healthy control group, the researchers also found changes in stress
hormones. The same changes are also seen in people with post-traumatic stress
PNES seizures belong under functional disorders, which is a collective term
for up to thirty physical diseases where it is not clear whether the disease is
physically or mentally contingent. A large part of the patients suffering from
PNES have been through exhausting and futile diagnostic process at hospitals
and psychiatric clinics before being referred to the Research Clinic for
Functional Disorders and Psychosomatics.
Michael Winterdahl assesses that the research results can have a bearing on
how the healthcare system deals with PNES patients.
“We have now finally demonstrated a biological cause for these
otherwise unexplained seizures. This knowledge alone can be enough to remove
the sense of powerlessness experienced by both patients and
practitioners,” says Michael Winterdahl. He can imagine the new knowledge
about NPY’s role being used to screen for vulnerability towards prolonged
stress in the future, perhaps even in the form of a simple blood sample like
those used in the study.
“We know that the amount of NPY that is released in a stressful
situation is genetically determined. Some people are genetically more resistant
to stress, while others are particularly vulnerable,” says Michael
Winterdahl, Alessandro Miani, Moana J. H. Vercoe, Antonia Ciovica, Lori
Uber-Zak, Charlotte Ulrikka Rask, Paul J. Zak. Vulnerability to psychogenic
non-epileptic seizures is linked to low neuropeptide Y levels. Stress,
2017; 1 DOI: 10.1080/10253890.2017.1378638