There are two groups: the healthy control group (n=12) and the patient group (n=26). The patient group recruits subjects diagnosed with first episode psychosis which occurred within 2 years and having been treated with antipsychotics for 1 year. Participants will complete clinical scales and undergo PET scans. Subjects in the patient group will receive a reduced intake of antipsychotics by 25% after each week of the four-week period in which they will also undergo PET imaging at the baseline, 7 week, and 8 week marks to detect the correlation between the capacity of presynaptic dopamine and relapse in the patients discontinuing treatment.