OBJECTIVE: The purpose of this study was to determine the dopamine D2
receptor occupancy induced by low-dose haloperidol treatment in a
prospective trial. METHOD: Seven patients with schizophrenia were treated
with 2 mg/day of haloperidol for 2 weeks, and D2 receptor occupancy was
measured by [11C]raclopride and positron emission tomography. RESULTS: The
patients showed high levels of D2 occupancy (53%-74%); five of them showed
substantial clinical improvement, and none showed important side effects.
CONCLUSIONS: The findings demonstrate that low doses of haloperidol induce
D2 receptor occupancies that are in the putative therapeutic range. In
combination with recent empirical trials, these findings should encourage
clinicians to initiate treatment of psychotic episodes with low (2-4 mg
haloperidol equivalent) doses of typical neuroleptics, particularly for
first-episode patients.Abstract Teaser