The study will be conducted as a single-center, randomized, double-blind, placebo-controlled, ascending dose study in up to 8 sequential cohorts of healthy subjects. Each cohort will enroll 8 subjects: 6 subjects will receive ITI-333 and 2 subjects will receive placebo as a single oral dose after a fast of at least 10 hours.

Key Inclusion Criteria:

• Healthy male and female subjects between 18 and 45 years old (inclusive);
• BMI inclusive of 18-32 kg/m2 at screening and a minimum weight of 50 kg;
• Willingness to remain in the clinic for the inpatient portion of the study and return for follow-up visit(s) as required by protocol and as deemed necessary by the Investigator;

Key Exclusion Criteria:

• Clinically significant abnormality within 2 years of Screening that in the Investigator's opinion may place the subject at risk or interfere with study outcome variables; this includes, but is not limited to, history of or current cardiac, hepatic, renal, neurologic, GI, pulmonary, endocrinologic, hematologic, or immunologic disease or history of malignancy;
• Clinically significant abnormal findings in vital sign assessments, including blood oxygen saturation (SAO2) < 96% and < 12 breaths per min; History of psychiatric condition that in the Investigator's opinion may be detrimental to participation in the study