Inclusion Criteria:  U.S Military Veteran between the age of 18 to 65 years old at time of screening. Preferred language for communication is English and able to read and speak English at a 6th grade level PTSD diagnosis as assessed by Clinician-Administered Posttraumatic Stress Scale (CAPS-5) Stable medication regimen for at least four weeks prior to the onset of study participation.  Exclusion Criteria:  History of opiate, cocaine, methamphetamine, benzodiazepine, or cannabis abuse as determined by the National Institute of Drug Abuse Quick Screen (NIDA-Q). Currently using opiates, cocaine, methamphetamines, benzodiazepines, or cannabis as evidenced by a positive urine drug screen prior to enrollment. Currently pregnant as determined by a positive urine pregnancy test prior to enrollment. Current clinically significant alcohol abuse in the past two weeks on the Quick Drinking Screen (QDS). Currently breastfeeding. Ongoing illness or physical health problem(s) that may be exacerbated by CBD (e.g., history of liver problems) History of significant allergic condition, significant drug-related hypersensitivity, or allergic reaction to cannabinoids. Concomitant medications with possible CBD-drug interactions (see section 81. Risks) Alanine transaminase (ALT) or Aspartate transaminase (AST) enzyme levels 3x normal limits. Concurrent engagement in trauma-related psychotherapy for PTSD. Current or past DSM-5 diagnosis of psychotic disorder or bipolar disorder (as determined on the Mini International Neuropsychiatric Interview (MINI 7.0)) Suicide attempt in the last year and/or suicide risk requiring immediate intervention or requiring a higher level of care than can be provided by the study treatment (as determined by the Self-Injurious Thoughts and Behaviors Interview (SIT-BI)).