Computed tomographic evaluation of patients with tardive dyskinesia.

X ray computed tomography has been used since its introduction to evaluate patients with tardive dyskinesia (TD). A critical review of the 18 reports which have appeared since 1976 suggests that TD may be associated with neuroanatomical abnormalities. In particular, a meta-analysis of the reports of ventricular brain ratio found a trend for patients with TD to have larger lateral ventricles than unaffected patients. The magnitude of the difference appears to be small, however, and several well conducted studies have reported negative results. A careful analysis revealed that low statistical power, concurrent neuroleptic treatment, insensitive measures of ventricular dilatation, and variable diagnostic criteria for TD may have led to negative findings in most of the investigations. The possible significance of these results and suggestions for further research are discussed.