Psilocybin-assisted Therapy for Post-Traumatic Stress Disorder in Survivors of Intimate Partner Violence

The goal of this randomized controlled trial is to evaluate the efficacy of psilocybin administered with Acceptance and Commitment Therapy (ACT) as an intervention to reduce post-traumatic stress disorder (PTSD) symptom burden in adult (aged 18-65) survivors of intimate partner violence (IPV). This trail will test the following 2 aims: AIM 1 : To compare the efficacy of a therapeutic psilocybin dose at improving outcomes on the PCL-5 and CAPS-5 as compared to an active control psilocybin dose in IPV survivors with chronic PTSD. AIM 2: To evaluate the efficacy of psilocybin on quality of life, cognitive function, motor ability, depression, anxiety, and cognitive flexibility. Participants will be asked to: * Complete a 2 part screening process * Attend a baseline assessment * Complete a psychoeducation preparation session(s) * Attend psilocybin administration session (receive high dose \[25mg\] or low dose psilocybin \[1mg\]) * Complete 5-6 weekly sessions of ACT * Repeat outcome measures at 1-week, 4 weeks, 3 months (online questionnaires only), and 6 months post-psilocybin administration.

Inclusion Criteria: * Individuals of all sexes, gender identities, and ethnicities * Ages 19 to 65 years at the time of screening * At least 6 months since last IPV incident * A score of 1 on the Composite Abuse Scale with repetition of abusive events * Minimum PCL-5 score of ≥ 33 * Limited lifetime use of serotonergic hallucinogens * Ability to read/write English Exclusion Criteria: * Severe or moderate substance use disorder other than nicotine in past 6 months * Lifetime diagnosis of schizophrenia or bipolar disorders (or first or second-degree relative) * Active suicidal ideation or serious attempt within the past 1 year. * Current pregnancy or nursing, trying to become pregnant * Any notable abnormality on ECG or routine medical blood laboratory test * Insulin-dependent diabetes; if taking oral hypoglycemic agent, then no history of hypoglycemia * Epilepsy with a history of seizures * Current or recent (within 12 weeks) participation in a clinical trial * Cognitive impairment (SLUMS score \