Impaired glucose tolerance and abnormal movements in patients with schizophrenia

Objective: Diabetes mellitus has been implicated as a risk factor for tardi ve dyskinesia. The authors examined the association between abnormal moveme nts and impaired glucose metabolism, which often precedes the development o f overt diabetes, in patients with schizophrenia. Method: Twenty-one patien ts with DSM-IV schizophrenia receiving neuroleptic medication were given or al glucose tolerance tests involving serial glucose and insulin levels. The se values were analyzed in relationship to abnormal involuntary movement ra tings. Results: Patients with impaired glucose tolerance had higher mean ab normal movement scores than those without glucose intolerance, but this dif ference was not statistically significant. There was, however, an associati on between the magnitude of the fasting insulin level and abnormal movement s after the authors controlled for fasting glucose level. Additionally, the fasting glucose level predicted abnormal movements after the authors contr olled for age. Conclusions: Hyperinsulinemia and hyperglycemia associated w ith insulin resistance may potentially contribute to the pathogenesis of ta rdive dyskinesia. Findings from this small cross-sectional study suggest a possible relationship that requires clarification through larger, longitudi nal studies.