Pharmacokinetic Study for IV Allopregnanolone

Inclusion Criteria: * Chronic Posttraumatic Stress Disorder * Generally healthy and not on any prohibited medications (that could affect study outcomes) * Willing to abstain from alcohol for 2 weeks and from nicotine, marijuana or illicit drugs for 4 weeks before experimental procedures and throughout the study * Females: must have a menstrual cycle and not be on hormonal birth control (with a few exceptions; see below) * If gender non-conforming: must not be on hormone therapy Exclusion Criteria: * Bipolar I disorder, schizophreniform disorder, or clinically significant psychotic symptoms apart from the presence of trauma-related sensory hallucinations or negative beliefs * Moderate or severe substance use disorder within three months of screening * Sleep Apnea * History of a suicide attempt within 1 year of enrolling * Imminent risk to self or others or requiring clinical intervention to maintain safety * Unstable medical condition or condition that may affect outcomes * Moderate or severe traumatic brain injury (TBI) (mild TBI acceptable; moderate TBI allowed for PK study) * Using any medications or substances (per self-report or toxicology testing) that may increase the risk for IV Allo side effects or affect the experimental results. * Unable to tolerate IV placement or blood drawing by needle stick * Wear hearing aids or fail hearing test (not applicable to PK study) * Females: pregnant, breastfeeding, or if of childbearing potential, unwilling to use two forms of ef…