• Ability to comprehend and provision of signed and dated informed consent form

• Stated willingness to comply with all study procedures and availability for the duration of the study (approximately 17 weeks from the date of being randomized)

• Individuals, between the ages of 18 and 75 years

• Allow digital recording of phone interviews

• PTSD related to military service

• Primary DSM-5 diagnosis of PTSD, assessed by structured interview using the CAPS-5

• Total CAPS-5 score 23

• ISI \>15

• Screening clinical laboratory tests without clinically significant abnormalities that would make study participation inappropriate, as determined by the site investigator with input, if needed, from the study chair

⁃ Electrocardiogram (ECG) at baseline without clinically significant abnormalities that would make study participation inappropriate, as determined by the site investigator with input, if needed, from the study chair and/or contingent upon approval by consulting medical physician.

⁃ Females of childbearing potential:

∙ Must have a negative pregnancy test during screening

‣ Must agree not to become pregnant or breastfeed during the course of the study

‣ Must be willing to use a reliable form of contraception for 16 weeks (during study treatment and for 2 weeks after taking the last dose) which includes: barrier contraceptives (male or female condoms with or without a spermicide, diaphragm or cervical cap with spermicide, or intrauterine device) and hormone-based therapy (contraceptive pills, intrauterine devices, or Depo-Provera®)

‣ Birth control for female participants is not necessary if surgically sterile or if with a partner with whom they are not capable of conceiving children (defined as a surgically sterile female by hysterectomy, bilateral oophorectomy, or bilateral tubal ligation; surgically sterile male who has undergone a complete orchiectomy or successful vasectomy; or a same sex partner)

⁃ Agree to secure firearms while receiving study treatment

⁃ If individuals are undergoing evidence-based psychotherapy (EBT), which includes cognitive behavioral therapy (CBT), cognitive processing therapy (CPT), prolonged exposure therapy (PE), and/or stress inoculation therapy (SIT), they must have started these therapies at least 60 days prior to starting screening. If screening is started, and it is then discovered that EBT was started within 60 days prior to screening, participants must wait at least 60 days since staring the new EBT before they can complete the screening ISI, the screening PCL, and the Phone Assessment. (Supportive individual and group therapy is allowed)

⁃ Agreement to adhere to Lifestyle Considerations (see Section 5.3) throughout study participation

⁃ Clinical evidence of adequately treated sleep apnea or absence of sleep apnea having a severity that would make study participation problematic, established by meeting one of the criteria below:

∙ Clinical evidence of adequately treated sleep apnea with a continuous positive airway pressure (CPAP) or alternative treatment device (as defined in Section 8.1) (Participants can be reevaluated at least 30 days after screen failure.)

‣ If clinically tested, sleep study negative for sleep apnea or results indicating an Apnea-Hypopnea Index (AHI) \< 23 within the past 6 months

‣ If tested for study eligibility, ApneaLink (or equivalent alternative device) result or other sleep study shows AHI \< 23.