Tardive dyskinesia predicts prolactin response to buspirone challenge in people with schizophrenia.

Prolactin response to buspirone was evaluated in patients with schizophrenia, with and without tardive dyskinesia (TD). Prolactin response in patients with schizophrenia without TD was significantly decreased, compared to healthy comparison subjects (F = 6.36, df = 5, p < 0.0001). Furthermore, prolactin levels after administration of buspirone were not significantly increased from baseline. In contrast, there was no prolactin response difference between patients with schizophrenia and TD and healthy subjects. This finding suggests that decreased dopamine (D(2)) receptor sensitivity may result in lower risk of developing TD and may lead to a fuller understanding of the variable expression of D(2)-receptor mediated side effects.