Saccadic hypometria in drug-naive and drug-treated schizophrenic patients: a working memory deficit?

In certain conditions patients with schizophrenia make markedly smaller (hypometric) saccades than controls. This hypometria has been thought to reflect dopaminergic blockade as a result of antipsychotic medication. We tested this hypothesis by comparing the performance of an antipsychotic-naïve group and an antipsychotic-treated group of first-episode schizophrenic patients on a predictive saccade paradigm. We explored the possibility that hypometria reflects a spatial working memory deficit by correlating performance on neuropsychological tests of mnemonic function with saccadic accuracy. Both the drug-naïve and treated schizophrenic patients made hypometric saccades when compared with a group of matched controls. Primary saccade amplitude also correlated significantly with performance on some of the neuropsychological tests. These results are discussed in terms of the roles of cortical dopamine and working memory deficits in schizophrenic patients.