1181 Rock Around the Clock: Non-24 Sleep-Wake Disorder Successfully Treated with Circadian Entrainment, a Case Series

Abstract Introduction Non-24-hour sleep-wake rhythm disorder (N24SWD) is a circadian rhythm disorder characterized by an inability to entrain to the 24-hour environment. It can occur in both blind and sighted individuals- usually with a longer sleep period, advanced temperature rhythm, and higher sensitivity to light than normal controls. Current therapies, derived from treating N24SWD in the blind and the human phase response curve, typically involve timed melatonin administration. It is more complex in sighted individuals, requiring multiple time cues such as light, melatonin, social interactions, feeding, and activity. We present two cases of non-24 sleep-wake disorder in sighted individuals who were successfully treated with circadian entrainment. Report of case(s) Report of Cases: Case 1: Sighted 31-year-old unemployed male with ADHD, presented with an irregular sleep pattern. He reported a lack of routine, prolonged dim basement computer use, and a circadian rhythm appearing longer than 24 hours. Actigraphy and sleep diaries confirmed N24SWD. Comprehensive measures, including timed light and melatonin therapy, blue light blocking glasses, and activity scheduling, led to a subjective "miraculous" improvement, with follow-up actigraphy confirming resolution. Case 2: Sighted 23-year-old female with autism and affective disorders presented with shifting sleep times alternating with prolonged video-game use. Actigraphy and sleep diaries were consistent with N24SWD. Following a prescribed schedule with light therapy, timed melatonin, and activity scheduling led to circadian alignment, confirmed by sleep diaries and patient report. Conclusion Effectively managing N24SWD in sighted individuals is challenging, as evidenced by limited treatment success and total cases documented in the literature, including challenges in long-term patient adherence. This case series highlights two successful instances of entrainment using a combination of timed melatonin, bright and low light therapy and activity scheduling, supported by actigraphy and diaries reflecting adaptation. These cases provide insights into contributors to the development of N24SWD and methods for resolving them. Support (if any)