Age at Onset and Delays in Diagnosis of Central Disorders of Hypersomnolence Over the Past 30 Years.

Patients with narcolepsy type 1 (NT1), type 2 (NT2), idiopathic hypersomnia (IH) usually suffer from symptoms for years, even decades, before being diagnosed. We aimed to assess age at onset, age at diagnosis and changes in the diagnostic delays of these patients from 1990 to 2020 in a single centre. Age at onset, age at diagnosis and diagnostic delays of patients with NT1, NT2 and IH were collected at the Reference Narcolepsy Centre, Montpellier-France. Age at onset for each disorder was categorised into three life periods (< 18, 18-25, > 25 years). Diagnostic delays were compared among disorders, taking into account sex, different life periods and time periods. NT1 was diagnosed in 415 patients (242 males), NT2 in 127 patients (68 males) and IH in 289 patients (75 males). Age at onset was not different between disorders (peak between 10 and 20 years in NT1, and 15-20 in IH and NT2). NT1 patients had the shortest diagnostic delays compared to NT2 and IH (median 4, 5 and 8 years respectively). Diagnostic delay is getting shorter in NT1 and IH over the last decades. In patients who started symptoms in childhood, diagnostic delays were the shortest in NT1 and the longest in IH. No sex difference in diagnostic delays was found in NT1 and NT2, but IH females had shorter delays than males. In conclusion, patients with NT1 and IH are diagnosed earlier nowadays compared to the 2000s. Increased public awareness and education efforts should be made to increase knowledge of the diseases and to early identify excessive daytime sleepiness.