Inclusion Criteria:
* Subjects 18 - 65 yrs with \> 15 % Total Body Surface Area Burns.
* National Stressful Events Survey Acute Stress Disorder Short Scale (NSESSS) average total score\>= 2 (severity scale of none (0), mild (1), moderate (2), severe (3), or extreme (4) ) prior to discharge from UUH.
Exclusion Criteria:
* Allergy or previous adverse reactions to ketamine
* Pending surgical interventions
* Active systemic infection, sepsis, or hemodynamic instability
* Physical limitations from burn injury that preclude safe travel to outpatient visits or positioning for therapy.
* Lack of reliable transportation, caregiver support, or housing stability.
* Language barrier
* Personal history or first- or second-degree relatives with schizophrenia, bipolar affective disorder, delusional disorder, schizoaffective disorder, psychosis, or other psychotic spectrum illness.
* Currently meeting DSM-5 criteria for Dissociative Disorder, or other psychiatric conditions judged to be incompatible with the establishment of rapport or safe exposure to ketamine.
* Currently meeting DSM-5 criteria for Cluster B Personality Disorder.
* Severe depression requiring immediate standard-of-care treatment (e.g., hospitalization).
* Suicidal ideation over the past month as assessed as a yes to question 3, 4, or 5 on the Columbia-Suicide Severity Rating Scale, Suicidal Ideation section
* Current or prior history of PTSD diagnosis
* Current or history within the last two years of meeting DSM-V criteria of substance use disorder (excluding caffeine and nicotine).
* Current substance use disorders may be identified through the drug urine screening test or undergoing treatment (methadone/Suboxone) .
* Congestive heart failure, including all New York Heart Association Classes.
* Angina pectoris, cardiac hypertrophy, cardiac ischemia, myocardial infarction
* Uncontrolled hypertension at the time of enrollment (BP\>140 systolic or 90 diastolic), coronary artery disease, artificial heart valve
* Prolonged or congenital long QT syndrome (\>450 ms), serious cardiac arrhythmias, tachycardia, a clinically significant screening ECG abnormality
* History of hypersensitivity to ketamine
* Receiving ketamine treatments for psychiatric condition within the past 6 months
* Seizure disorder
* Moderate to severe dementia
* History of significant traumatic brain injury
* Requires the use of supplemental oxygen.
* Require Propranolol for Burn Hypermetabolism
* Any other condition that would, in the Investigator's judgment, contraindicate the subject's participation in the clinical study due to safety concerns or compliance with clinical study procedures (e.g., infection/inflammation, intestinal obstruction, unable to swallow medication, \[patients may not receive the drug through a feeding tube\], social/ psychological issues, etc.)
* Subjects taking prohibited medications. A washout period of prohibited medications for a period of at least five half-lives should occur prior to study registration. These medications include antipsychotic medications, doses of benzodiazepines in excess of 20mg diazepam equivalents per day.
