Abstracts

Rationale: Psychiatric comorbidity is a common risk factor in Psychogenic Nonepileptic Seizures (PNES). Whether chronic pain is a significant risk factor in PNES remains unclear. The current study examines the rate of chronic pain in PNES patients with or without apparent psychopathology and explores whether individuals with comorbid chronic pain differ in seizure burden and psychiatric distress compared to those without chronic pain. Methods: PNES patients seen at the Cleveland Clinic Epilepsy Center between 2008 and 2015 were retrospectively identified. Patient-completed health status measures and diagnosis information were extracted from the Knowledge Program Data Registry and chart review was conducted to confirm diagnoses. The primary outcome of interest was seizure burden, defined as reporting fewer than weekly or at least weekly seizures in the four weeks prior to the encounter. The primary predictor of interest was chronic pain comorbidity, particularly its effect on reported initial seizure frequency and mood independent of psychiatric comorbidities. Mood was measured as probable depression (PD), defined as Patient Health Questionnaire (PHQ-9) score ?- 10. Logistic regression analyses were conducted with 95% confidence intervals and significance value set at 0.05. Results: Two hundred eighty-nine PNES patients were included, of whom 71.6% had a comorbid chronic pain diagnosis, 65.1% had a comorbid psychiatric diagnosis, and 47% of the sample had both comorbidities. Of those PNES patients, 24.2% had comorbid chronic pain diagnosis only and 17.7% had comorbid psychiatric diagnoses only. When compared to PNES patients with neither chronic pain nor a psychiatric diagnosis, patients with chronic pain but without a psychiatric diagnosis (n = 70) had more than three times greater odds of having PD (OR = 3.22, 95% CI 1.32 ?" 8.21, p = .014), while those with both chronic pain and a psychiatric diagnosis (n = 137) had 2.9 times greater odds of PD (OR = 2.87, 95% CI 1.15?" 6.57, p = .023). Depression moderated the association between chronic pain and seizure burden. Among patients with both chronic pain and psychiatric diagnoses, those with PD had almost five-fold greater odds of reporting at least weekly seizures (OR = 4.9, 95% CI 2.22 ?" 10.94, p < .001), when compared with patients who did not report PD. Conclusions: In the present study, chronic pain is found to be a common comorbidity in PNES to a comparable extent with psychiatric comorbidities, indicating that treatment plan for PNES should also incorporate chronic pain management. Findings also revealed that PNES patients with comorbid chronic pain but without a comorbid psychiatric diagnosis were more likely to have probable depression than those with identified psychiatric diagnoses, warranting mental health attention to the PNES patients with comorbid chronic pain. Funding: None