Non-24-Hour Sleep-Wake Circadian Rhythm Disorder in a Sighted Male With Normal Functioning.

This is a rare case of non-24-hour sleep-wake rhythm disorder in a sighted male with normal functioning. The patient, a 23-year-old doctorate graduate student, presented with difficulty falling asleep and excessive daytime sleepiness. He reported variable sleep and wake times. Overnight baseline polysomnography was unremarkable and his Multiple Sleep Latency Test was significant for short mean sleep latency. Sleep diary and actigraphy were obtained, which demonstrated a pattern of delaying of sleep and wake times each day. He had excellent symptom response to nightly melatonin.