Vol.:(0123456789) 1 3 Sleep and Biological Rhythms https://doi.org/10.1007/s41105-019-00237-w ORIGINAL ARTICLE The influential factor of narcolepsy on quality of life: compared to obstructive sleep apnea with somnolence or insomnia Mei Ling Song 1  · Keun Tae Kim 2  · Gholam K. Motamedi 3  · Yong Won Cho 2 Received: 28 October 2018 / Accepted: 14 August 2019 © Japanese Society of Sleep Research 2019 Abstract Narcoleptics tend to have a low quality of life (QoL). Few studies have compared QoL in narcolepsy against other sleep disorders. The purpose of this study was to investigate QoL and its influential factors in narcolepsy patients compared to obstructive sleep apnea (OSA) with somnolence and primary insomnia. We enrolled 63 narcoleptics (33 type 1, 30 type 2), 49 patients with OSA with somnolence, and 87 insomniacs. All patients were diagnosed through detailed clinical face-to-face interviews and polysomnography and had no other comorbid sleep disorders or medical diseases. All patients completed the Korean-version of the Short-Form 36-Item Health Survey (K-SF36) and a series of standard sleep-related questionnaires. The QoL of the narcolepsy group was comparable to the OSA with somnolence and insomnia groups. There was no significant difference between type 1 and type 2 narcolepsy on the total score of the K-SF36. However, factors that had the most impact on QoL included anxiety followed by depressive mood for narcoleptics, depressive mood followed by severity of insomnia for OSA with somnolence, and insomnia severity followed by depressive mood for insomniacs. Mood disturbances, mainly anxiety, affected QoL most in narcolepsy patients. Excessive daytime sleepiness and nocturnal sleep disturbance did not directly affect QoL of narcoleptics. To improve QoL in narcoleptics, proper management of anxiety should be considered as part of the treatment. Keywords Narcolepsy · Quality of life · Cataplexy · Excessive daytime sleepiness Introduction Narcolepsy is a neurological sleep disorder characterized by excessive daytime sleepiness (EDS) caused by loss of hypo- cretin (orexin) in postero-lateral hypothalamus. Narcolepsy is classified as narcolepsy with cataplexy (type 1, NT1), or without cataplexy (type 2, NT2) [1]. The prevalence of type 2 and type 1 narcolepsy lies between 0.16–0.66% and 0.025–0.05%, respectively [2]. While there is no reported prevalence for narcolepsy in the Korean adult population, in a study of 20,407 Korean adolescents the prevalence of narcolepsy with cataplexy in the younger age groups was determined as 0.015% [3]. Narcoleptics often experience more difficulties in their social, vocational, and personal lives. Patients with narco- lepsy report higher rates of comorbid medical and/or psychi- atric problems, and often present with additional sleep disor- ders [4, 5]. Thus, it can be understood that narcolepsy has a negative influence on quality of life (QoL) [6, 7]. However, the exact factors that adversely affect QoL in these patients are not well known. Excessive daytime sleepiness, a major symptom of narcolepsy with considerable effects on QoL, has been reported in 91% of narcoleptics [8]. In obstructive sleep apnea (OSA), EDS/somnolence is also commonly reported [9] with a negative influence on QoL [10]. A previous study reported that the QoL in narcolepsy patients was lower than in OSA patients [11]; however, it did not exactly differenti- ate between narcolepsy and OSA with somnolence (OSA- som), and to our knowledge no other study has compared QoL between narcolepsy and OSA-som (Korean version of Epworth sleepiness scale, K-ESS ≥ 10). Therefore, it would * Yong Won Cho neurocho@gmail.com 1 College of Nursing, Daegu Health College, Daegu, South Korea 2 Department of Neurology, Dongsan Medical Center, Keimyung University School of Medicine, 56 Dalseong-ro, Jung-gu, Daegu 41931, South Korea 3 Department of Neurology, Georgetown University Hospital, Washington, DC, USA