Clinical challenges in narcolepsy: From delayed diagnosis to daytime function impairments during treatment

While a delayed diagnosis of narcolepsy is common, the reasons are not well understood. Additionally, only few systematic studies have focused on the daytime function of treated patients. In this cross-sectional online survey, we aimed to investigate the predictive factors for diagnostic delays and daytime dysfunction in Japanese patients with narcolepsy undergoing treatment.

This survey included individuals aged 16 years or older with a confirmed diagnosis of narcolepsy. The participants completed a questionnaire related to disease diagnosis and current daytime function, including quality of life measured with Short Form-8 (SF-8) and work performance measured with the Work Productivity and Activity Impairment (WPAI) questionnaire.

The study enrolled 248 of the 250 respondents. The mean time from symptom onset to definitive diagnosis was 8.7 years. Diagnostic delay was significantly associated with the year of symptom onset (<2005 vs. ≥2005), age at symptom onset (<16 vs. ≥16 years), narcolepsy type (without or with cataplexy), residence (rural vs. urban), and information sources about the disorder. The participants had a lower mental component summary score in SF-8 and higher WPAI absenteeism, presenteeism, and overall work impairment scores than the general Japanese population. Severe daytime sleepiness (Epworth Sleepiness Scale score ≥16) and younger age were associated with a poor mental component summary score and higher presenteeism and overall work impairment.

Improving sleepiness is crucial to optimize the patients' daytime functioning. A treatment system that addresses regional disparities in narcolepsy care is needed, along with increased public awareness, especially in educational settings.