Delayed Sleep Timing in Teens Study

Inclusion Criteria: * Age 16-19 years * Currently in 11th or 12th grade and enrolled in a traditional high-school; or cyber school with synchronous classes (not home-schooled) * Physically and psychiatrically healthy, as determined by instruments described below * Provision of written informed consent and assent Additional inclusion criterion for Experimental protocol * Meets operational definition of delayed sleep phase (DSP; weekend bedtime ≥1 AM) Exclusion Criteria: * Significant or unstable acute or chronic medical conditions * Past or current bipolar disorder or psychotic disorder * Past or current substance use disorder other than alcohol use disorder or cannabis use disorder * Past month recreational drug use other than alcohol, cannabis, and nicotine * Current syndromal sleep disorders other than insomnia and delayed sleep phase disorder * Medications that interfere with sleep and/or reward function (antidepressants, and stimulants prescribed for ADHD are permitted) * Conditions that would interfere with the MRI procedures (e.g., non-removal ferromagnetic devices)