National Sleep Foundation

Chapter 4: Primary Hypersomnias


The prevalence among the general population is estimated at around 50 per 1 million individuals. Among patients seen in sleep centers, patients with idiopathic hypersomnia are five to ten percent less common than patients with narcolepsy. A large study of 6,000 sleep patients at a respiratory sleep center found that 1 percent of the patients seen had idiopathic hypersomnia.69


  1. Bassetti C, and Y Dauvilliers, “Idiopathic Hypersomnia,” In: Kryger MH, Roth T III, Dement WC, eds. Principles and Practice of Sleep Medicine (5th edition), Philadelphia, Pa: Elsevier Saunders; 2011:969-979.