This will be a randomized placebo controlled study to test the efficacy of cannabidiol (CBD) as a treatment for symptoms of post-traumatic stress disorder (PTSD). Subjects, 120 in total, will be males and females with PTSD, half of which will have comorbid mild traumatic brain injury (TBI). There will be three study arms, each with 40 subjects: 1) Oral CBD 400 mg daily; 2) Oral CBD 800 mg daily, and 3) Placebo daily. Treatment duration will be 8 weeks. The primary outcome will be change in PTSD symptoms as measured by change in the Clinician-Administered PTSD Scale (CAPS-5) total score.

Inclusion Criteria:

• Meets clinical criteria for Posttraumatic Stress Disorder (PTSD) as per Clinician-Administered PTSD Scale for DSM-5 (CAPS-5)
• TBI present (for PTSD+TBI subjects only) as per American Congress of Rehabilitation Medicine (ACRM) definition
• Mild TBI (for PTSD+TBI subjects only) as per Ohio State University Identification Screener
• Able to provide at least 2 locators
• Able to provide informed consent
• Confirmation that the participant is reliably domiciled
• Agreement to abstain from all other cannabinoid use for the duration of the study
• Willingness to use contraception if of childbearing potential.

Exclusion Criteria:

• History of open head injury
• TBI within the last 6 months
• Moderate or Severe TBI
• SUD in the last 12 months other than mild AUD or nicotine use
• Use of any cannabinoid containing product within the last 1 month
• Positive urine drug screen (Positive for cannabinoids, amphetamine, cocaine, opioids)
• Currently prescribed medications with possible CBD-drug interactions
• Lifetime history of any psychiatric disorder with psychotic features, bipolar disorder
• Exposure to trauma in the last 30 days, including police duty or military service
• Psychotherapy for PTSD or other psychiatric conditions initiated within 2 months of screening
• Not stable for at least 2 months on psychiatric medication, anticonvulsants, antihypertensive medication, sympathomimetic medication, estrogen replacement therapy, medications associated with neurogenesis, or steroid medication
• Active suicide attempt within the past year
• Current significant suicidality (assessed using the C-SSRS), any significant suicidal behavior in the past 12 months, or any history of serious suicide attempts requiring hospitalization, or current significant homicidality.
• Neurologic disorder or systemic illness affecting CNS function (apart from TBI)
• Major medical illness (i.e. cancer or infectious disease.)
• Clinical diagnosis of anemia, advised by physician to avoid blood draws
• Significant laboratory abnormalities, significantly impaired hepatic function, abnormalities in complete blood count or metabolic panel
• Significant allergic reactions to the drug including cannabinoids or sesame oil
• Pregnancy or lactation
• Contraindication to MRI
• Males and females who plan to conceive a child during or two weeks following the study
• Active legal problems likely to result in incarceration within 12 weeks of treatment initiation
• Has a high risk of adverse emotional or behavioral reaction (e.g., evidence of serious personality disorder, antisocial behavior, serious current stressors, and lack of meaningful social support).
• Inpatient psychiatric treatment in past 12 months, with the exception of detox and extended ED stays.

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices).

Beginning 9 months and ending 36 months following article publication or as required by a condition of awards and agreements supporting the research.

The investigator who proposed to use the data. Upon reasonable request and to achieve aims in the approved proposal. quests should be directed to Esther.Blessing@nyulangone.org. To gain access, data requestors will need to sign a data access agreement.