Psychogenic non-epileptic seizures and functional motor symptoms: A common phenomenology?

Recent studies have attempted to compare patients affected by psychogenic non-epileptic seizures (PNES) to patients affected by functional motor symptoms (FMS) from a demographic, clinical and psychological perspective. Nevertheless, results are quite controversial and significant conclusions have not been drawn. The aim of our study was to evaluate the phenomenology of psychology of the two groups assessing levels of dissociation and its subcomponents, alexithymia and interoceptive sensitivity in patients with PNES and in patients with FMS.

We conducted a cross-sectional study recruiting 20 patients with PNES, 20 patients with FMS and 20 healthy subjects as a control group. All subjects underwent: Dissociative Experience Scale (DES), Somatoform Dissociation Questionnaire (SDQ-20), Cambridge Depersonalization Scale (CDS), Toronto Alexithymia Scale (TAS-20), Hamilton Rating Scale for Depression (HAM-D), Hamilton Rating Scale for anxiety (HAM-A), heart beat detection task.

Our data suggest that PNES group scored significantly higher than the healthy control group on a measure of detachment (CDS). Also at the DES, a measure of psychoform dissociation, PNES patients scored significantly higher than healthy subjects. On the other hand patients affected by FMS scored significantly higher than the healthy control group on the SDQ but they did not report more experiences of detachment on the CDS. Patients affected by PNES and FMS were significantly more alexithymic than healthy controls, with a third of them scoring >61 on the TAS-20.

Our data show different psychological mechanisms underlying patients with PNES and patients with FMS. This might lead also to potential implications for treatment.