Medical comorbidities in patients with psychogenic non-epileptic seizures (functional seizures)

We investigated medical comorbidities in patients with psychogenic non-epileptic seizures (PNES). We hypothesized that these patients commonly have significant medical comorbidities.

In this retrospective study, all patients with PNES, who were diagnosed at Shiraz Comprehensive Epilepsy Center, Iran, from 2008 until 2019, were investigated. Age, gender, age at seizure onset, seizure semiology, and characteristics, known medical (organic) comorbidities reported by the patients and video-electroencephalography recordings of all patients were registered routinely.

During the study period, 272 patients with PNES-only had the inclusion criteria and were studied. Sixty-five patients (24%) reported having a medical (organic) comorbidity. The most commonly reported medical comorbidity was thyroid disorder. Age at onset (OR: 1.058; 95% CI: 1.026-1.090; p = 0.0001), duration of disease before the diagnosis (OR: 1.071; 95% CI: 1.025-1.119; p = 0.002), and sex (female) (OR: 1.97; 95% CI: 1.016-3.834; p = 0.04) were significantly associated with having medical comorbidities.

While we did not have a control group to provide the number and type of medical problems that are expected in the general population, and therefore our results should be interpreted with caution, we had some intriguing observations. About one quarter of patients with PNES reported having medical comorbidities. The exact nature of the relationship between medical illnesses and PNES is not clear; however, hypothetically they could have a complex relationship. This study provides valuable information on the frequency and nature of medical comorbidities in patients with PNES and opens new horizons for future research.