Inclusion Criteria:
All participants must meet all of the following criteria:
* Aged 15-18 years old, inclusive
* Must agree to inform the investigators within 48 hours of any emergent medical conditions and procedures
* Able to lie still on their back for up to 1 hour
* Must not be pregnant
* Must agree not to participate in any other interventional clinical trials during the duration of the study
* Must be willing to comply with all study procedures
* Agree to have study visits video and/or audio recorded, including consent visit, clinical assessments (for staff training) and in-laboratory sleep visits (recording deleted within one month of study visit).
* A primary parent or guardian is willing participate in the study and to provide informed consent
* Are fluent in or predominantly speaking and reading in English
In addition, PTSD and TEC youth must satisfy the following criteria:
\- Must have a history of at least one traumatic event of any type, as defined by the DSM-V. This may include exposure to physical or sexual abuse, witnessing violence against loved ones or friends, traumatic accidents, natural disasters, death of a close family member etc.
Additional criteria for PTSD youth:
\- At baseline, meet threshold for DSM-5 criteria for current severe PTSD, as determined by the semi-structured clinical interview (KSADS).
Exclusion Criteria:
* Caregiver or adolescent is unwilling or unable to give adequate informed consent.
* Are likely, in the investigator's opinion and via observation during the screening and clinical assessment period, to be re-exposed to their index trauma or other significant trauma, lack social support, or lack a stable living situation during study participation.
* Any finding(s), based on the screening process, that the PI feels would make the study unsuitable for the participant.
* Participation in the last 30 days in a clinical study involving an investigational drug
* MRI contraindication
* Claustrophobia or inability lie still in the scanner after practice MRI sessions.
* Any participant presenting current serious suicide risk, as determined through the KSADS, responses to C-SSRS, and/or clinical judgment of the investigator, will be excluded; however, history of suicide attempts is not an exclusion. Would present a serious risk to others as established through clinical interview and contact with treating physician.
* Neurodevelopmental disorders such as autism spectrum disorder
* Intellectual Disability (IQ less than 70, per self-report)
* Currently impaired by any medical condition that would prevent study participation
* Traumatic brain injury with ongoing symptoms, including headache, visual disturbances, and/or impairments in concentration.
* Neurological disorder(s) such as seizures, epilepsy, or brain tumors (Tourette's disorder, as diagnosed in the KSADS, is not exclusionary for TEC/PTSD youth)
* Current use of medications or other drugs (i.e., alcohol) in a manner that may interfere with sleep.
* Possible pregnancy
Exclusions for Typically developing youth:
* No history of or current psychopathology, as defined in the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS), with exception of past specific phobia.
* Current diagnosis of a sleep disorder (self-report).
* Any history of any traumatic experience as defined by the DSM-V, including IPV exposure, neglect, or emotional abuse etc.
PTSD Youth:
\- Current diagnosis of or history of psychotic disorder, bipolar disorder, or autism spectrum disorder diagnosed by the KSADS interview. No other co-morbid disorders are exclusionary.
TEC Youth:
\- A current diagnosis of PTSD or a current diagnosis of or history of psychotic disorder, bipolar disorder, or autism spectrum disorder diagnosed by the KSADS interview.
