Many adolescents go to bed late and wake up early for school. Science is only beginning to understand how sleep schedules can affect them. The investigators are interested in whether changing adolescents' sleep patterns affects their functioning, attention, and how they feel. The investigators are especially interested in the effects of changing both how much sleep adolescents get and when that sleep happens.

This study focuses on healthy 13-17-year-olds with ADHD. This study asks adolescents to systematically change their sleeping habits across a 3 week span. The first week, they follow a sleep schedule that fits reasonably well with the schedule they keep when they do not have to wake up early for any specific obligation (e.g., for school). The second week, they spend several nights in a "short sleep" condition, during which they get 6.5 hours in bed per night. The final week, they enter a sleep condition that allows for healthy sleep duration, but with a timing that is randomly assigned to either fit well with their preferred schedule or fit poorly with that schedule. During each week, they and their parents complete measures of their attention and other factors. At the end of each week, they attend an evening session to measure their internal body clock ("circadian phase"), as well as measures of attention and other thinking skills. The goal is to understand whether the benefits of healthy sleep duration depend on the timing of when that sleep occurs.

Inclusion Criteria:

• Ages 13-17 years at time of informed consent/assent
• Based on semi-structured clinical interview, participants must meet full DSM-5 criteria for ADHD inattentive or ADHD combined presentation.

Exclusion Criteria:

• Non-traditional school setting (morning-afternoon Monday-Friday).

• Exclusionary diagnoses. We will exclude adolescents with known intellectual disability, autism spectrum disorder, psychosis, bipolar disorder, or neurologic conditions (e.g., epilepsy), per caregiver-report.

• Exclusionary sleep disorders. We will exclude adolescents with symptoms of obstructive sleep apnea or periodic limb movement disorder based on published cutoffs on a validated questionnaire.

• High caffeine intake. To promote adherence to directives not to consume caffeine the day of office visits without withdrawal effects, adolescents with daily intake of >1 coffee or "energy drink" or >2 caffeinated sodas per day based on caregiver- and adolescent-report will be excluded.

  • Unwillingness or inability to take part in study procedures (e.g., visits, prescribed sleep conditions).
  • Medication use or unwillingness to discontinue melatonin and/or stimulant medications during the 3-week study protocol.

• Refusal to refrain from automobile driving during the sleep restriction condition.

• "Intermediate" Chronotypes (neither morning larks nor night owls) based on habitual sleep timing on nights when adolescent has no morning obligations such as school or work.

Per sponsor policy, primary outcome data will be shared with the NIMH Data Archive (NDA).

Per NDA guidelines, data will be uploaded every 6 months throughout the study. Longevity of those data will be determined by the NIMH.

To access study data within NDA, users must submit at Data Request Checklist to NDA, sign the NIMH NDA Data Use Agreement, and submit proof of IRB approval. The Data Request Checklist will specify that data must be used for research purposes only, data will not be shared or sold, attempts will not be made to identify individual participants, etc. The NDA Data Access Committee will decide which requests to grant based on the information submitted. If given access, data access will be granted for one year but this is renewable. Should individuals or organizations request the dataset directly from the investigators, those requests will be directed to the NDA to retrieve the data.