Abstracts

Rationale: One third of patients with newly diagnosed epilepsy have a mood disorder. Yet, the impact of seizures themselves on mood are unknown. Investigating this link may provide insights into mechanisms of depression as a comorbidity of epilepsy. We aimed to characterize changes in mood in epilepsy patients admitted to the Epilepsy Monitoring Unit (EMU) before and after experiencing a seizure.

Methods: We enrolled patients with epilepsy aged 18-100 admitted to the NYU Langone EMU from 2021 through 2023. Upon admission, subjects completed the Beck Depression Inventory-II (BDI-II) and a trained assessor administered the Montgomery-Asberg Depression Rating Scale (MADRS). The MADRS was repeated four to twenty four hours and two to seven days after a seizure. Those who did not have a seizure served as controls and the MADRS was repeated two to four days after admission and two to seven days after discharge. We calculated changes in MADRS with a positive change as a worsening of mood and a negative change as an improvement in mood.

Results: A total of 38 subjects (male=22, female=16) with a mean age of 35.74 ±10 years were included. Thirty participants had a seizure (focal to bilateral or generalized tonic-clonic convulsion (TCC): n=15; focal impaired awareness (FIA): n=15), and eight were controls. Experiencing a seizure predicted a change in MADRS scores after 4-24 hours in either direction compared to controls (Fisher’s, p=0.053). Clinically significant postictal change in MADRS (i.e. ≥ 6 points; Turkoz I et al., 2021) were more likely to be an improvement in mood (Fisher’s, p=0.009). Those with higher BDI-II scores (i.e. high depression severity prior to seizures) were more likely to experience mood improvement four to twenty four hours after a seizure (Pearson's, r=-0.66, p=0.001). Furthermore, those with postictal improvement in mood had higher BDI-II scores (M=18.94, SD=2.20 – i.e. mild depression) compared to those who experienced worsening of mood (M=9.25, SD=2.54 – i.e., minimal depression) (One-way ANOVA, p = 0.022; Tukey’s HSD, p=0.020). The association between higher BDI-II scores and mood improvements weakened two to seven days after a seizure (Pearson’s, r=-0.38, p=0.046). Relevant covariates had a lack of effect (medication tapering, inpatient therapy, sleep deprivation, seizure duration, number of seizures, seizure onset, length of stay, and depression diagnosis).

Conclusions: Seizures are associated with postictal improvement and worsening of mood. Those with a postictal improvement in mood were more likely to report higher levels of depressive symptoms pre-ictally, indicating a subset of patients with epilepsy may experience a therapeutic effect from seizures on mood state. Elucidating the mechanisms behind these short-lived mood shifts could help unravel the complex bidirectional relationship between depression and epilepsy, provide insights into potential therapeutics for this comorbidity, and serve as a model for understanding depression as a psychiatric disorder.

Funding: Parekh Center for Interdisciplinary Neurology and Finding a Cure for Epilepsy and Seizures (FACES)