Despite popular belief, delays in diagnosing narcolepsy may not have improved.

Click image to view full-size PDF.

This study analyzed data from 1272 adults with self-reported central disorders of hypersomnolence (CDH) who completed a Project Sleep online survey between March and April 2021 that included questions about year of diagnosis as well as time between symptom onset and diagnosis.

The number of CDH diagnoses increased steadily over time with a dramatic jump in 2009 / 2010. For each calendar year, the ratio of individuals with short delays (<3 years to diagnosis, lowest quartile) and long delays (>15 years, highest quartile) was calculated. This short/long delay ratio did not correlate to calendar year (r=-0.036). Overall there was no clear evidence of a reduction in time to diagnosis in the last decades. Changes may be obscured by the population’s age and rising rates of CDH diagnosis (new and old cases) over the last two decades. The 2009/2010 surge in NT1 and NT2 diagnoses could be linked to the H1N1 flu pandemic and Pandemrix® vaccine, alongside increased awareness and internet access. 

Leary EB, Flygare J, Oglesby L, Maski K, Barateau L. Evolving Diagnostic Patterns in Central Disorders of Hypersomnolence: Has Time to Diagnosis Gotten Shorter Over the Last Decades? Sleep 47(suppl_1), May 2024 (Late Breaking Abstracts).