Could a common sleep pill boost PTSD treatment in veterans?

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

Inclusion Criteria: * (same for Phase 1 and Phase 2): * men and women * a history of US military service * capable of reading and understanding English * able to provide written informed consent * Criterion A event meets DSM-5 criteria and occurred during military service, including combat and military sexual trauma * Chronic full PTSD diagnosis \>3 months duration as indexed by CAPS-5 at screening, and CAPS-5 score \> 30 * Insomnia indicated by insomnia severity index (ISI) score \> 14 * Subjects on non-exclusionary medications, and must be on a stable dose for at least 4 weeks prior to randomization, including Selective Serotonin Reuptake Inhibitors (SSRIs, e.g.,): * sertraline * paroxetine * fluoxetine * fluvoxamine * citalopram * escitalopram * Serotonin-norepinephrine reuptake inhibitors (SNRIs; e.g.): * Desvenlafaxine * Duloxetine * Levomilnacipran * Venlafaxine * For subjects who are in psychotherapy, treatment must be stable for 6 weeks * Women of child-bearing potential must not be pregnant or have plans for pregnancy or breastfeeding during the study and must use a medically acceptable method of birth control Exclusion Criteria: * Moderate or severe DSM-5 alcohol or cannabis use disorder in the last 3 months * Mild alcohol use disorder with abstinence of 30 days will be allowed * Mild marijuana use disorder will be allowed with abstinence for one week prior to participation * Any other DSM-5 drug use disorder in the last 3 months will be excluded * Lifetime bipolar disorder I or II, schizophrenia, schizoaffective disorder, obsessive-compulsive disorder, or major depressive disorder with psychotic features * Exposure to trauma in the last 3 months * Use of exclusionary antidepressant (trazodone, mirtazapine, doxepin, tricyclics), mood stabilizers (e.g., lithium), antipsychotic medication * Prominent suicidal or homicidal ideation or any suicidal behavior in the past 3 months on the Columbia Suicide Severity Rating Scale (C-SSRS) or increased risk of suicide that necessitates additional therapy or inpatient treatment * Pre-existing moderate sleep apnea or positive screen for sleep apnea by type III device (AHI\>15) in the absence of adherence to effective treatment (such as CPAP or oral device) * Night shift work or extreme morning or evening tendencies in order to avoid the impact of circadian factors on subjective and objective sleep measures * Neurologic disorder or systemic illness affecting CNS function * Chronic or unstable medical illness, including: * unstable angina * myocardial infarction within the past 6 months * congestive heart failure * preexisting hypotension or orthostatic hypotension * heart block or arrhythmia * chronic renal or hepatic failure * pancreatitis * severe chronic obstructive pulmonary disease * History of severe traumatic brain injury as assessed by the Ohio State University Traumatic Brain Injury Identification Method (OSU-TBI ID) * Uncorrected hearing impairment * Mild cognitive impairment assessed by the Montreal Cognitive Assessment (MOCA) * Pregnancy, breastfeeding and/or refusal to use effective birth control (for women) * Previous adverse reaction to a hypnotic * Current use of benzodiazepines, strong inhibitors of CYP3A, or Digoxin * The investigators will require that all participants do not consume heavy amounts of alcohol per week (\>7 drinks for women, \>14 drinks for men) or use illicit drugs for one week prior to participation