No D2 receptor increase in PET study of schizophrenia.

To the Editor.— Densities of D2dopamine receptors in postmortem brain tissue from schizophrenic patients have been found to be higher than those in control brains.1,2The pathophysiologic significance of this finding has been questioned, since elevated receptor densities may be caused by neuroleptic treatment.3It is now possible to examine D2dopamine receptor binding in the brains of living human subjects by means of new brain-imaging techniques and radiolabeled receptor ligands. Using a gamma camera and77Br-Bromospiperone, Crawley et al4reported evidence of a slight increase in D2dopamine receptors in a group of schizophrenic patients. Using positron emission tomography (PET) and11CN-Methylspiperone, Wong et al5recently reported a twofold to threefold elevation of D2dopamine receptor densities in the major basal ganglia of ten drug-naive and five previously treated schizophrenic patients. We previously used PET and