This is an open-label, single-dose study of up to 4 dose levels of ITI-333 in healthy male and female subjects. Each cohort will enroll 6 subjects. Subjects will have a baseline PET/CT scan and a postdose PET/CT scan using [14C]-MDL100907 to characterize 5-HT2A receptor occupancy

Inclusion Criteria:

• Healthy male and female subjects between 18 and 45 years old (inclusive);
• BMI inclusive of 18.0-32.0 kg/m2 at screening and a minimum weight of 50 kg;
• Willing to be confined to the clinical research unit for the duration of the inpatient period of the study;

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, gastrointestinal (including history of gastric bypass), pulmonary, endocrinologic, hematologic, or immunologic disease or history of malignancy;
• Clinically significant abnormal findings in vital sign assessments, including blood oxygen saturation (SpO2) < 96% and respiratory rate < 12 breaths per min;
• History of psychiatric condition that in the Investigator's opinion may be detrimental to participation in the study;
• Any condition which would preclude MRI or PET/CT examination (eg, implanted metal, claustrophobia, unable to fit in PET/CT or MRI scanners).