Clinical Research Directory

Inclusion Criteria: * Willing and able to consent to the study * Agree to comply with requirements and procedures * Veteran who has served in a branch of the US armed forces * Between ages 18-60 * Report using cannabis within the past three years but not more than twice in the past month * Exposure to Criterion A stressor defined by CAPS-5 and identified by Life Events Checklist-5 (LEC-5); trauma does not have to be related to combat or military service * Significant PTSD severity as indicated by CAPS-5 diagnosis and/or score \>= 25 of at least one month prior to study entry, PTSD is patient's primary concern * not currently receiving any psychotherapy for PTSD Exclusion Criteria: * Pregnant, lactating or are a heterosexually active, pre-menopausal woman who is NOT using medically approved birth control (e.g., oral or depot contraception, contraceptive implant, IUD, condom/foam, sterilization, tubal ligation) * Current or past diagnosis of any bipolar or related disorder or schizophrenia spectrum and other psychotic disorder as determined by the SCID-5 or previous diagnosis by a licensed psychologist or psychiatrist * Determined to be at high risk for suicide requiring immediate intervention based on the C-SSRS and/or clinician judgment * Meet criteria for substance use disorder other than Cannabis Use Disorder or Alcohol (Mild or Moderate) or Nicotine Use Disorder, determined by the SCID-5 * Presence of contraindications, current or past allergic or adverse reaction, or known sensitivity to smoking cannabis * Concomitant treatment with medication taken daily that has level 1 evidence indicating severe drug-drug interactions with cannabis * Currently receiving psychotherapy for PTSD or previously received exposure-based PTSD treatment * Current diagnosis or evidence of significant or uncontrolled hematological, endocrine, cerebrovascular, cardiovascular, systemic, pulmonary, pulmonary fibrosis, or other forms of restrictive lung disease, immunocompromising, or neurological disease * Current diagnosis of a mood, anxiety, or other disorder that is more clinically salient than PTSD * Cognitive exhibit impairment * Lack of fluency in English * Insufficient memory of the index traumatic event * Pervasive development disorder history * Seeking or currently undergoing treatment for Cannabis Use Disorder. * Traumatic brain injury (TBI) with current cognitive impairment related to TBI * Exclusively left-handed (score of -100 on Handedness Questionnaire) * claustrophobic * MRI contraindications (e.g., ferrous metal in head/body)