Can cannabis help veterans overcome PTSD? new study aims to find out.

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

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)