Pain Sensitization and Habituation in a Model of Experimentally-induced Insomnia Symptoms

1. Screening Procedures: For this research study, the screening procedures include the following activities. Participants will first complete questionnaires and have an interview where they will be asked questions concerning general health status and sleep-wake habits. Also during this visit, a study nurse will collect a small blood sample that will be used to test for a number of markers of general health status.

If it appears that the participant may be eligible for participation, s/he will be introduced to an electronic diary that will be emailed every morning and evening to monitor sleep-wake patterns, mood, pain, and other health-related information.

Following the medical screening (visit 2), the physician will determine if the participant is eligible to proceed to the overnight sleep study. This consists of sleeping overnight in the laboratory during the usual sleep time.

Seven days before participation in the in-hospital portion of the study, a member of the study team will ask the participant to follow the study sleep-wake schedule. Sleep will be monitored with an electronic sleep diary and the participant will wear an actigraphy watch, which will help to evaluate sleep and measure the light level exposure before starting the study. 2. Randomization Procedures: Each participant will complete both parts of the study protocol, i.e., the experimental condition (where participants will undergo repeated cycles of sleep disruption, 18 days total in the Clinical Research Center) and the control condition (where participants will have a sleep opportunity of 8 hours every night; 18 days total in the Clinical Research Center). 3. Research Procedures: If a participant qualifies to take part in this research study, s/he will be required to stay in the hospital for two 18 day long research protocols. These protocols will take place at least 2-3 months apart. The experimental protocol includes 3 nights of 8 hour-sleep per night followed by three 4-day cycles, each consisting of 3 nights of shortened and disrupted sleep, followed by a single night of 8 hour recovery sleep. After the last cycle, the participant will have two more nights with 8 hours of sleep per night. In the control protocol, these 18 days will be 8-hour sleep nights.

During the stay in the hospital, research staff will accompany the participant during all waking times. The staff will help the participant to stay on the schedule, maintain wakefulness, and make sure that equipment is recording properly.