Ketamine-assisted Psychotherapy for Adolescent PTSD (KAP)

Inclusion Criteria: * Aged 15-17 years old, inclusive * At baseline, meet threshold for Diagnostic and Statistical Manual (DSM-5) criteria for current PTSD as determined by the CAPS-CA. * Medically and neurologically healthy on the basis of physical examination, medical history, and the clinical judgement of the evaluating study medical provider * Must agree to inform the investigators within 48 hours of any emergent medical conditions and procedures * If of childbearing potential, must have a negative pregnancy test at study entry and prior to each KAP dosing session, and must agree to use adequate birth control through 10 days after the last KAP dosing session. * 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 * A primary parent or guardian is willing to provide informed consent * Are fluent in or predominantly speaking and reading in English 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 Preparatory 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. * Current diagnosis of or history of a psychotic disorder, bipolar disorder, or autism spectrum disorder diagnosed by the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS) interview and clinician judgement. No other co-morbid disorders are exclusionary. * Intellectual disability (IQ\<70) per medical history * History of moderate to severe substance use disorder, as determined by the KSADS and/or clinician judgement (excluding tobacco), or active substance use (including current alcohol use or positive urine toxicology) * Any prior exposure to sub-anesthetic doses of ketamine (including prior research or clinical psychiatric treatment with ketamine and/or recreational use) * Any participant presenting current serious suicide risk, as determined through the KSADS, responses to Columbia Suicide Severity Rating Scale (C-SSRS), and/or clinical judgment of the investigator, will be excluded; however, history of suicide attempts prior to enrollment is not an exclusion. * Would present a serious risk to others as established through clinical interview and contact with treating physician. * Current use benzodiazepines, opiates, or lamotrigine, which are hypothesized to interfere with ketamine's mechanism of action * High blood pressure (BP) at the time of screening, defined by the Centers for Disease Control and Prevention (CDC) to be BP greater than 130/80. * Persons who have previously received ketamine therapeutically or taken it recreationally. * Are pregnant, nursing, or are able to become pregnant and are not practicing an effective means of birth control. * Persons who are known to have a hypersensitivity to ketamine * Participants that are deemed not to be medically and neurologically healthy on the basis of physical examination, medical history, and the clinical judgement of the Study Medical Provider or qualified designee in order to participate. * Examples of medical rule-outs include but are not limited to: unstable hypertension, recent severe neurologic injury, a history or current signs/symptoms of liver or renal insufficiency, and current diagnoses of cardiac, vascular, pulmonary, gastrointestinal, endocrine, neurologic, hematologic, rheumatologic, or metabolic disorders that are deemed clinically significant based on investigator judgement.