This study will assess the adverse events, tolerability, and how bretisilocin intramuscular (IM) Injection moves through the body of healthy adult Japanese, Han Chinese, and Non-Asian volunteers participants.

Inclusion Criteria:

• Group 1: Healthy adult Japanese male or female;

  • Japanese participants must be first-generation Japanese of full Japanese parentage residing outside of Japan for less than 5 years.

• Group 2: Healthy adult Han Chinese male or female

  • Han Chinese participants must be first-generation Han Chinese of full Chinese parentage residing outside of China for less than 5 years.

• Group 3: Healthy adult male or female volunteers of African, European, or Latin American descent.

• A condition of general good health, based upon the results of a medical history, physical and neurological examination, vital signs, laboratory profile and 12-lead ECG.

Exclusion Criteria:

• Current diagnosis or history of any clinically significant mental health disorder, cardiovascular disorder, metabolic disorder, or other disorder requiring pharmacologic or other medical treatment. (Previous psychological support without a diagnosed history of a mental health disorder would not be considered exclusionary.)
• Clinically significant personal or familial history (first degree relative) of epilepsy, seizures, convulsions, or other seizure disorder (excluding febrile seizures as a child), previous head trauma or other risk factor for seizure (e.g., electrolyte disturbances, or structural neurological disorders).
• Any use of psychoactive substances (including ketamine, esketamine, MDMA, cannabinoids, or nitrous oxide) during the 6 weeks prior to confinement.