Post-traumatic stress disorder (PTSD) is a psychiatric disorder than may develop following a traumatic event including serious incidents, natural or human-caused disasters, violence, death of a loved one, receipt of traumatic news, or serious illness/hospitalization. While half of US adults experience trauma in their lifetime, most do not develop PTSD. However, those who do develop the disorder may have significant impairments and risk for functional dysfunction across multiple domains. While short term symptoms are the most common, some individuals develop chronic PTSD. These individuals may experience frightening and intrusive thoughts and memories of the event (flashbacks), have sleep disturbances, feel numb or detached, and be easily startled (hypervigilance). This trial is a double-blind placebo controlled study of cannabidiol (CBD) for symptoms of PTSD in adults using liquid structure Formulation (Nantheia ATL5). Participants complete three weeks of baseline data collection including assessments of activity and sleep. Intervention is Nantheia ATL5 or placebo. Dose is initiated at 400mg BID and maintained over 8 weeks. Standardized symptom profile measurements, clinician assessments, laboratory testing, collection of inflammatory biomarkers, and suicide screening is completed throughout. Age- and gender-matched healthy population participants are enrolled and complete baseline data collection only. All participants may complete optional functional magnetic resonance imaging (fMRI).