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July 1992

In Vivo Occupancy of Dopamine Receptors by Antipsychotic Drugs-Reply

Author Affiliations

Department of Psychiatry Harvard Medical School Brockton Veterans Affairs Medical Center Psychiatry (116A) 940 Belmont St Brockton, MA 02401
Cambridge, Mass
Forest Hills, NY
Belmont, Mass
Cambridge, Mass

Arch Gen Psychiatry. 1992;49(7):590. doi:10.1001/archpsyc.1992.01820070084021

In Reply.—  We do not agree that the raters in the study by Berenbaum were able to distinguish normal subjects from schizophrenic patients on the thought disorder scale that Berenbaum used. Berenbaum was able to show differences between hospitalized schizophrenic twins and nonschizophrenic cotwins1(p12) on three categories of thought disorder on the scale he used: "nonsequitur," "derailment," and "tangential responses." Only one of the nine categories of thought disorder (tangential responses) tested produced differences between nonhospitalized schizophrenic twins and the unaffected cotwins.1 But one cannot re- gard the unaffected cotwins of schizophrenic patients as a normal control group. Indeed, there was no normal control group in that study, which Berenbaum et al also point out as a "limitation."1We previously noted,2 in response to the initial letter by Berenbaum,3 several other methodologic problems in his study. First, the thought disorder raters were minimally trained American undergraduate