Does Missing Medication Acutely Change Seizure Risk? A Prospective Study

OBJECTIVE: The objective of this study was to determine whether missing individual doses of anti-seizure medications (ASMs) elevate short-term seizure risk in people with drug-resistant epilepsy. METHODS: In a prospective, community-based cohort, adults with drug-resistant epilepsy (≥ 3 seizures/month) or their caregivers recorded seizures and ASM intake with smartphone applications for 10 months each. Individual level analysis modeled the relationships between ASM adherence with seizure occurrence, as well as with a simplified seizure forecast via a 90-day moving average ("Napkin method"). Group-level analysis with a mixed-effects model was performed to examine the relationship between ASM adherence and simplified forecasts, while controlling for differences in individual seizure frequency via random effects. RESULTS: Twenty-seven participants (median age = 29 years) contributed 7,853 person-days. Individual analysis showed that only a small (n = 2) number of participants had a weak relationship between ASM adherence with seizure occurrence. Group-level analysis showed that seizure occurrence was highly linked to the Napkin method, but not ASM adherence. INTERPRETATION: Among individuals with frequent, drug-resistant epilepsy, occasional missed ASM doses did not measurably raise immediate seizure risk. Whereas sustained nonadherence remains a clinical concern, clinicians may reassure patients that infrequent brief lapses are unlikely to trigger seizures acutely, yet they should continue emphasizing overall adherence for long-term seizure control. ANN NEUROL 2026;99:1076-1082.