Inclusion Criteria:

• * Recruited from SOF with an active duty history of at least 5 years.
• * Subjects may be in active duty or retired, male and female, between the ages of 40 and 60 years old.
• * The participants must have a confirmed diagnosis of PTSD, identified by Posttraumatic Stress Disorder Checklist for DSM-5 (PCL-5) scores higher than 40.
• * The participants must have been on a stable pharmacological or psychotherapeutic therapy for at least three months (if applicable), and continue this treatment throughout the duration of the study.
• * They must be able and willing to consent for the study. Individuals who are able to become pregnant must adhere to a medically accepted method of contraception (eg. hormonal birth control, barrier birth control, intrauterine device, abstinence).

Exclusion Criteria:

• * Existing Horner syndrome;
• * Allergy to local anesthetics or contrast;
• * Previous history of stellate ganglion block with psychosis;
• * Admission to in-patient psychiatric facility within last 3 months;
• * History of moderate of severe TBI;
• * Currently pregnant or breastfeeding;
• * Current substance use disorder, or test positive for 1 or more illegal or controlled drugs on the initial urine drug screen, such as cocaine, marijuana, amphetamines, opioids, benzodiazepines, amongst others;
• * Previous behavioral health diagnoses (bipolar I, psychosis, etc);
• * Currently undergoing exposure therapy.