Treatment outcome of non-24-hour sleep–wake rhythm disorder: a retrospective study of 24 consecutive cases in a sleep clinic

• Main Authors: Marina Hirose, Chiaki Arakawa, Akiko Watanabe, Yuichi Esaki, Ryoko Kawai, Nakao Iwata, Tsuyoshi Kitajima
• Format: Article
• Language: English
• Published: Fujita Medical Society 2018-08-01
• Series: Fujita Medical Journal
• Subjects: n24swd; free-run; circadian rhythm; prognosis; treatment
• Online Access: https://www.jstage.jst.go.jp/article/fmj/4/3/4_2017018/_pdf/-char/en
• ISSN: 2189-7247; 2189-7255

Objectives: Reports on the treatment outcome of non-24-hour sleep–wake rhythm disorder (N24SWD) are limited because of low prevalence. We retrospectively analyzed it using stoppage of free-run as the primary index. Methods: We enrolled 24 consecutive patients who visited the sleep clinic of the Department of Psychiatry of Fujita Health University Hospital and were diagnosed with N24SWD according to the International Classification of Sleep Disorders, Third Edition. Data were retrospectively collected from medical records. When a stopped free-run was identified in an individual during the treatment period, the patient’s clinical state was determined as one of four defined categories based on the extent of the clinical improvement, including “normalization” (i.e., normalized sleep-phase for >3 months). Chronobiological interventions (e.g., bright light therapy, ramelteon administration, and hospitalization) that were considered to have a temporal association with free-run stoppage were also examined. Results: “Normalization” occurred in 12.5% (3/24 patients) and free-run stoppage occurred in 45.8% (11/24), whereas free-run persisted throughout the course in 45.8% (11/24). The drop-out rate during the treatment course was 54.2% (13/24 patients). No single intervention achieved “normalization,” and patients with free-run stoppage tended to undergo multiple chronobiological interventions. Conclusions: The very low “normalization” rate and the large number of patients with ongoing free-run who dropped out suggest that N24SWD is extremely refractory. The possibility of free-run stoppage using a combination of multiple chronobiological interventions may be plausible, although we were unable to identify a specific treatment that was effective. Further studies that include the analysis of therapeutic interventions are required.