Subjective Experience and D₂ Receptor Occupancy in Patients With Recent-Onset Schizophrenia Treated With Low-Dose Olanzapine or Haloperidol: A Randomized, Double-Blind Study

Abstract

A level of D(2) receptor occupancy between 60% and 70% is optimal for subjective experience of patients with recent-onset schizophrenia. Substantial interindividual variation in D(2) receptor occupancy was seen at fixed low-dose levels of olanzapine and haloperidol. Olanzapine, 7.5 mg/day, showed no superior subjective response over haloperidol, 2.5 mg/day. Olanzapine may need to be dosed higher than 7.5 mg/day for most patients with recent-onset schizophrenia, and haloperidol needs to be individually titrated in the very low dose range to reach optimal occupancy.