We are grateful to Weinberger and colleagues for responding to our prediction1 that diagnosis-byside interactions with respect to brain structure should be detected in MRI studies of monozygotic twins discordant for schizophrenia. The findings they report fail to fulfill this prediction.
In that the laterality comparisons relate to anatomic differences that Weinberger et al have already identified between schizophrenic and well twins, we agree that the observations are relevant to our contention that disturbances in lateralization are at the heart of the disease process in schizophrenia. However we doubt that the findings abstracted from this study provide a definitive answer to this question for the following reasons.
None of the comparisons relates to temporal horn size, the measure that proved to be the most effective discriminator between patients with schizophrenia and normal subjects in our own study.
In a number of studies, ventricular enlargement has been reported to