Patients with psychogenic nonepileptic seizures and suspected epilepsy: An antiseizure medication reduction study.

Objective: To examine predictors of ASM reduction/discontinuation and PNES reduction/resolution in patients with PNES with a confirmed or strong suspicion of comorbid ES.

Methods: A retrospective analysis of 271 newly diagnosed Patients with PNESs admitted to the EMU between May 2000 and April 2008, with follow-up clinical data collected until September 2015. Forty-seven patients met our criteria of PNES with either confirmed or probable ES.

Results: Patients with PNES reduction were significantly more likely to have come off all ASMs by the time of final follow-up (21.7 vs. 0.0%, p = 0.018), while documented generalized (i.e. epileptic) seizures were much more common in patients with no reduction in PNES frequency (47.8 vs 8.7%, p = 0.003). When comparing patients that reduced their ASMs (n = 18) with those that did not (n = 27), the former were more likely to have neurological comorbid disorders (p = 0.004). When comparing patients with PNES resolution (n = 12) vs not (n = 34), those with PNES resolution were more likely to have a neurological comorbid disorder (p = 0.027), had a younger age at EMU admission (29.8 vs 37.4, p = 0.05) and a greater proportion of patients with ASMs reduced in EMU (66.7% vs 30.3%, p = 0.028). Similarly, those with ASM reduction had more unknown (non-generalized, non-focal) seizures (33.3 vs 3.7%, p = 0.029). On hierarchical regression analysis, a higher level of education and absence of generalized epilepsy remain as positive predictors of PNES reduction (p = 0.042, 0.015), while the presence of some other neurological disorder besides epilepsy (p = 0.04) and being on more ASMs at EMU admission (p = 0.03) were positive predictors of ASM reduction by final follow-up.

Significance: Patients with PNES and epilepsy have distinct demographic predictors of PNES frequency and ASM reduction by final follow-up. Patients with PNES reduction and resolution had higher level education, less generalized epileptic seizures, younger age at EMU admission, more likely to have presence of a neurological disorder besides epilepsy, and a greater proportion of patients had a reduction in the number of ASMs in the EMU. Similarly, patients with ASM reduction and discontinuation were on more ASMs at initial EMU admission and also were more likely to have a neurological disorder besides epilepsy. The positive relationship between reduction in psychogenic nonepileptic seizure frequency and discontinuation of ASMs at final follow-up elucidates that tapering medication in a safe environment may reinforce psychogenic nonepileptic seizure diagnosis. This can be reassuring to both patients and clinicians, resulting in the observed improvements at the final follow-up.