DOPAMINE D-2 DENSITIES AND THE SCHIZOPHRENIC BRAIN

Meta-analytic methods were used to test the D-2 dopamine density hypot hesis in schizophrenia. Post-mortem as well as in-vivo (i.e., PET and SPECT) neuroimaging studies that met criteria for inclusion into the m eta-analysis were gathered from 1980 to 1996. The mean effect size acr oss studies corresponds to an effect size of 1.47 (d). Although large, the effect size obtained does not meet heuristic benchmark criteria t hat would suggest D-2 density increases to be a marker for schizophren ia. That is, roughly 30% of patients with schizophrenia could not be d iscriminated from normal healthy controls. Based on the findings, it i s argued that D-2 density receptor increases in patients with schizoph renia, although a reliable finding in many patients (i.e., approximate ly 70%), is not a specific or consistent marker for schizophrenia. (C) 1998 Elsevier Science B.V. All rights reserved.