Somatization, dissociation and general psychopathology in patients with psychogenic non-epileptic seizures

The etiology of psychogenic non-epileptic seizures (PNES) remains uncertain. Previous studies have shown that PNES patients are characterized by high levels of somatization, dissociation and general psychopathology but a correlation of measures of these features and PNES severity or outcome has never been demonstrated, although this would strengthen a possible etiological link. This study measured somatization (Screening Test for Somatoform Symptoms-2), dissociation (Dissociative Experience Scale, DES), and general psychopathology (Symptom Checklist-90-Revised, SCL-90) in 98 patients with PNES and 63 patients with epilepsy. All mean scores were raised in the PNES compared to the epilepsy group. However, only measures of somatization and general psychopathology discriminated between patients with PNES and epilepsy in a logistic regression model (even when patient gender was controlled for). In PNES patients, high somatization scores correlated with poor outcome and greater seizure severity even after correction was made for dissociation and psychopathology. Dissociation and psychopathology scores were not independently associated with outcome or severity. The results suggest that, as a group, patients with PNES are best characterized by their tendency to express psychosocial distress by producing unexplained somatic symptoms which are brought to medical attention. Although dissociation may be relevant in some individuals it does not appear to be an independent factor across the whole PNES patient group.