Background and purpose: The aim of this study was to investigate the demographic variables and clinical characteristics of behaviorally induced insufficient sleep syndrome (BIISS) and to compare it with the other major hypersomnia disorders.
Patients and methods: One-thousand two-hundred forty-three consecutive patients referred to the outpatient clinic for complaint of excessive daytime sleepiness (EDS) were retrospectively investigated.
Results: The rate of BIISS in patients with EDS was 7.1%, predominant in males. The mean age of initial visit was younger than that for obstructive sleep apnea syndrome (OSAS), while the mean age of onset of symptoms was older than that for idiopathic hypersomnia, narcolepsy, and circadian rhythm sleep disorders. The mean Epworth sleepiness scale (ESS) score before treatment was lower than that for narcolepsy but higher than that for both OSAS and circadian rhythm sleep disorders. Twenty-two percent of BIISS cases reported having accidents or near-miss accidents during the five-year period preceding the investigation, and this group showed higher ESS scores than the group without accidents.
Conclusions: Our findings showed that an unignorably large number of people suffer from BIISS, and that people with severe cases of the disorder are at high risk for getting into an accident. Characteristics and demographic information could be helpful for making a differential diagnosis of BIISS.