IntroductionLennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC)-associated epilepsy are rare conditions associated with severe childhood-onset epilepsy. Caregivers play a critical role in the patients’ care and may experience significant psychosocial and socioeconomic burden. This cross-sectional study determined the burden of caring for patients with these rare epilepsy conditions in Japan. MethodsA quantitative online survey was used to assess patients’ and caregivers’ characteristics and the caregivers’ emotional state, among others. Several validated questionnaires were used: the Hospital Anxiety and Depression Scale (HADS; 0–21 score) assessed the caregivers’ emotional wellbeing, the Pediatric Quality of Life Inventory Family Impact Module (PedsQL FIM; 0–100 score) assessed the health-related quality of life (HRQoL) of the caregivers and their families, and the Work Productivity and Activity Impairment General Health (WPAI:GH; 0–100 % score) questionnaire assessed work productivity. ResultsA total of 36 caregivers responded (median [interquartile range (IQR)] age 43.5 [39.5, 48.3] years; 33/36 [92 %] female; 13/36 [36 %] working part-time and 13/36 [36 %] not working). Participants cared for 7/36 (19 %), 19/36 (53 %), and 10/36 (28 %) patients with LGS, DS, and TSC, respectively (median [IQR] age, 11.0 [6.8, 16.3] years; age at first seizure, 0 [0, 0] years). Patients received a median (IQR) of 4 (3, 5) treatment drug types. Patients experienced median (IQR) 3.0 (0, 21.0) epileptic seizures in the previous week; 28/36 (78 %) had severe intellectual disabilities, and 34/36 (94 %) had developmental delays. Caregivers reported stress (17/36 [47 %]), sleep problems (13/36 [36 %]), and anxiety (12/36 [33 %]). They spent a median (IQR) of 50.0 (17.5, 70.0) hours caregiving in the previous week, with 3.0 (1.0, 11.0) hours of seizure-specific care. Caregivers reported that their lives would be easier with a median (IQR) of 1.5 (0, 5.0) hours fewer per week caring for patients during/following seizures. Median HADS scores were 9.5 (‘suspected anxiety diagnosis’) and 7.5 (‘no depression’) for caregivers, and PedsQL FIM Total median score was 60.1, indicating HRQoL impairment for the caregiver and their family. WPAI:GH scores for paid workers indicated important work impairment. Higher caregiving hours (≥ 21 h vs. < 21 h in the previous week) resulted in higher caregiver burden as indicated by the HADS Total score (p = 0.0062) and PedsQL FIM Total score (p = 0.0007). ConclusionsCaregivers of patients with LGS, DS, or TSC in Japan experience a significant time burden, reduced HRQoL, and high level of work/activity impairment. Caregivers provide round-the-clock care to patients and rely on family and specialized caring services to help manage the increased caregiving time, which tends to be associated with greater emotional burden and HRQoL impact.