Stopped: Unique provision in the American Recovery and Reinvestment Act prevented approval of second year no-cost-extension in which completion of analyses were planned.
This research project consists of a three part study with five embedded sub studies. The first study phase identifies "body rhythms" of sleepiness/wakefulness and of melatonin levels for each subject (including sub-study 1). The second study phase identifies the optimum dose and timing of melatonin for regulating each individual's 24-hour sleep/waking cycle (including sub-study 2). The third study phase introduces a new independent variable, light (including sub-studies 3 and 4). Sub-study 5 is an optional longitudinal study. Sub-study 1 looks at how keeping a regular sleep schedule affects the body's natural rhythm. Sub-study 2 looks at how individuals metabolize melatonin. Sub-study 3 tests how individuals' endogenous melatonin production responds to bright outdoor light and Sub-study 4 tests a previous finding that artificial bright light exposed daily behind the knee can regulate the body clock. Sub-study 5 is an optional longitudinal study, an extension of the first study stage, for subjects whose rhythms are not clearly free-running.
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Treatment Effects on Circadian Phase Will be Assessed During Each Trial by Measuring the Timing of Endogenous Melatonin Secretion.
Timeframe: 1 year