The study will be conducted as an open-label and single-center study to evaluate the occupancy of ITI-1284 to the dopamine D2 receptor, serotonin 2A (5-HT2A) receptor, and serotonin transporter (SERT) in healthy subjects.

This study consists of up to 3 sequential parts. Part A will evaluate the D2 receptor occupancy for ITI-1284 at three dose levels. Part B will evaluate the 5HT-2A receptor and SERT occupancy for ITI-1284 at one dose level. Part C will evaluate the late postdose receptor occupancy of ITI-1284 on the D2 or 5-HT2A receptor at one dose level.

Inclusion Criteria:

• Healthy male and female subjects between 18 and 55 years old (inclusive);
• BMI inclusive of 18-32 kg/m2 at screening and a minimum weight of 50 kg;
• Willingness to remain in the hospital research unit for the duration of the inpatient period.

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, pulmonary, endocrinologic, hematologic, or immunologic disease or history of malignancy;
• Clinically significant abnormal findings in vital sign assessments, supine SBP > 140 mmHg or < 90 mmHg, or supine DBP >90 mmHg or < 50 mmHg or supine pulse rate > 100 bpm or < 45 bpm at Screening;
• 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);
• Contraindications based on any previous MRI or the study MRI performed prior to the baseline PET/CT scan.