Cognitive dysfunction in schizophrenia: organic vulnerability factor or state marker for tardive dyskinesia?

The literature on the putative association between cognitive dysfunction in schizophrenia and the presence of tardive dyskinesia is critically reviewed, focusing on potential artifacts and specific relationships to a particular topography of involuntary movements. These issues are exemplified via a study of cognitive function in 64 schizophrenic patients, in which impaired cognitive flexibility was identified as the primary measure distinguishing those with tardive orofacial dyskinesia. The significance of such an association with cognitive dysfunction is considered in relation to competing hypotheses of organic vulnerability to vs. state marker for this movement disorder.