Racial Differences in Circadian and Sleep Mechanisms for Nicotine Dependence, Craving, and Withdrawal

On day 1, participants will complete study assessments and will be fitted with an Actiwatch and instructed to continue a fixed time in bed (8 hours duration with no more than 20 min deviation) centered on habitual sleep (e.g., 11:00 p.m. to 7:00 a.m.). Naps will not be allowed. Following the one-week baseline sleep stabilization, participants will engage in the sleep restriction condition (4 hours, TIB \[Time in Bed\]; 1:00 a.m. to 5:00 a.m.). On the day of each sleep study, participants will be admitted to University of Alabama Birmingham (UAB) Highlands Hospital sleep unit at 7:00 p.m. and do an initial CO breathe test and fill out study questionnaires and a timeline follow-back procedure Participants will monitored for smoking withdrawal. Every 2 hours, participants to fill out various questionnaires. Participants will repeat the same conditions as the first night. After a two-week washout, participants will be crossed over to the alternate sleep extension/restriction condition.

sleep extension On day 1, participants will complete study assessments and will be fitted with an Actiwatch and instructed to continue a fixed time in bed (8 hours duration with no more than 20 min deviation) centered on habitual sleep (e.g., 11:00 p.m. to 7:00 a.m.). Naps will not be allowed. Following the one-week baseline sleep stabilization, participants will engage in the sleep extension condition (10 hours, (TIB); 10:00 p.m. to 8:00 a.m.). On the day of each sleep study, participants will be admitted to University of Alabama Birmingham Highlands Hospital sleep unit at 7:00 p.m. and do an initial CO breathe test and fill out study questionnaires and a timeline follow-back procedure Participants will monitored for smoking withdrawal. Every 2 hours, participants to fill out various questionnaires. Participants will repeat the same conditions as the first night. After a two-week washout, participants will be crossed over to the alternate sleep extension/restriction condition.