Clinical Research Directory

Inclusion Criteria: * Cisgender women who are at least 18 years old. * Meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for current PTSD secondary to sexual assault (i.e., index trauma is sexual assault that occurred 6 or more months in the past). * CAPS-5 score of 25 or higher at Baseline. * Are able to swallow pills. * Are willing to be driven home after the Dosing Session with a family member or caregiver or trusted transportation. * Are able to complete all protocol-required assessment tools without any assistance or alteration to the copyrighted assessments, and to comply with all study visits. * If able to become pregnant (i.e., with uterus and associated reproductive organs, fertile, following menarche and until becoming post-menopausal unless permanently sterile), must have a highly sensitive negative pregnancy test at study entry and prior to the Dosing Session, and must agree to use adequate birth control through 10 days after the Dosing Session if sexually active with a biologically male partner. Adequate birth control methods include intrauterine device (IUD), injected, implanted, intravaginal, or transdermal hormonal methods, abstinence, oral hormones plus a barrier contraception, vasectomized sole partner, or double barrier contraception. Two forms of contraception are required with any barrier method or oral hormones (i.e. condom plus diaphragm, condom or diaphragm plus spermicide, oral hormonal contraceptives plus spermicide or condom). * Must agree to inform the clinical investigators within 48 hours of any medical conditions and procedures. * Are proficient in speaking and reading English. * Agree to have all clinic visit sessions recorded to audio and/or video. Participants may opt out of the data analysis of the recordings. * Agree to the following lifestyle modifications: a light breakfast 2 to 3 hours before dosing is permitted, however, participants will refrain from caffeine and nicotine 2 hours prior to dosing sessions and at least 6 hours after dosing, abstain from alcohol for 24 hours prior to dosing, not enroll in any other interventional clinical studies during the duration of the study, be driven home after the Dosing Session, and commit to medication dosing, therapy, and study procedures. * Agree to refrain from beginning new medication and/or psychotherapy treatment. * Continued treatment with SSRIs will be permitted if participants have been on a stable dose for 3 months or longer prior to enrollment. However, participants must be tapered off of monoamine oxidase inhibitors (MAOIs) prior to dosing. In addition, participants may remain in stable (\> 3 months) psychotherapy. * May have well-controlled hypertension that has been successfully treated with anti-hypertensive medicines. * May have asymptomatic Hepatitis C virus (HCV) that has previously undergone evaluation and treatment as needed. * May have alcohol or substance use disorder if participant is not in withdrawal or requiring detox. Participants must have a plan, agreed upon by the principal investigator or designated physician, to reduce use of alcohol or other substances and to manage symptoms without self-medicating. Enrollment will require that, in the judgment of the principal investigator or designated physician, the plan for decreasing substance use is realistic and has a good chance of succeeding in order to prevent substance use from impacting the safety or efficacy of the investigational treatment. * May have a history of or current Diabetes Mellitus (Type 2) if additional screening measures rule out underlying cardiovascular disease, if the condition is judged to be stable on effective management, and with approval by the principal investigator or designated physician. * May have hypothyroidism if taking adequate and stable thyroid replacement medication. Exclusion Criteria: * Male * Condition impairing oral intake or digestive absorption. * Are not able to give adequate informed consent. * Significant suicide risk as defined by suicidal ideation with intend and a plan as endorsed on items 5 on the C-SSRS within the past 3 months * Have any current problem which, in the opinion of the principal investigator or designated physician, might interfere with participation. * Would present a serious risk to others as established through clinical interview and contact with treating therapist. * Have a history of, or a current primary, schizophrenia, schizoaffective disorder or any form of psychotic disorder, major depressive disorder with psychotic features, bipolar affective disorder type 1, or personality disorders. * Require ongoing concomitant therapy with a psychiatric medication with exceptions described below (see Section 6.6). * Have received Electroconvulsive Therapy (ECT) within 12 weeks of enrollment. * Have evidence or history of recent stroke (\< 6 months from signing of ICF), recent myocardial infarction (\< 6 months from signing of ICF), or clinically significant arrhythmia within 1 year of signing the ICF. * Have evidence or history of significant (controlled or uncontrolled) hematological, endocrine, cerebrovascular, cardiovascular, coronary, pulmonary, renal, gastrointestinal, immunocompromising, or neurological disease, including seizure disorder, or any other medical disorder judged by the investigator to significantly increase the risk of psilocybin administration. * Have uncontrolled hypertension using the standard criteria of the American Heart Association (values of 140/90 milligrams of Mercury \[mmHg\] or higher). * Abnormal and clinically significant results on vital signs, ECG, or laboratory tests at screening and baseline * Have symptomatic liver disease. * Are pregnant, nursing, or able to become pregnant and are not practicing an effective means of birth control if sexually active with a biologically male partner. * Have hypersensitivity to any ingredient of the study drug. * Positive urine drug screen for illicit drugs or drugs of abuse prior to the Dosing Session. Any positive urine drug test will be reviewed with participants to determine the pattern of use and eligibility will be determined at the investigator's discretion. * Current enrollment in any investigational drug or device study or participation in such within 30 days of screening. * Other personal circumstances and behavior judged to be incompatible with establishment of rapport or safe exposure to psilocybin or completion of clinical study procedures (e.g., active participation in legal proceedings).