Dual diagnosis of epilepsy and dissociative seizures: Prescription patterns, feasibility and safety of rationalising antiseizure medication

Background: Patients with a dual-diagnosis of epilepsy and dissociative seizures (DS) have received far less attention than those with single pathology. Anti-seizure medication (ASM) prescription patterns and safety of rationalisation have not been reviewed. Methods: We undertook a retrospective cohort study of all patients with a dual-diagnosis admitted to the Scottish Epilepsy Centre between 2012-2020. ASM frequencies were compared across admission, discharge and followup and emergency hospital attendances compared a year before and after admission. Demographic data, seizure characteristics and mortality data were also reviewed. Results: Across the 139 patients included in our study, ASM frequency at follow-up was significantly lower than on admission (mean 2.51 vs 2.14, Z = -2.11 p = 0.035, r = -0.215). Total hospital attendances in the year following admission were significantly lower than in the year before (mean 1.27 vs 0.77, Z = 2.306, p = 0.021, r = -0.262). Those with inactive epilepsy had their medications reduced to a greater extent that those with active epilepsy. 44 patients had their ASM frequency reduced during admission with a similar trend of reduced hospital attendances (mean 1.29 vs 0.43 Z = -3.162 p = 0.002). There was one epilepsy related death. Conclusions: Clinicians should consider the development of co-morbid DS in patients with epilepsy not responding to an escalation of ASM, especially if presenting with a new seizure type. Patients with a dualdiagnosis of epilepsy and DS, particularly those with well controlled epilepsy, are likely overtreated with ASM. Medication review in a tertiary epilepsy centre allows for safe rationalisation of ASM and likely contributes to the need for fewer hospital attendances.