Neuroleptic treatment is an unlikely cause of elevated dopamine in thalamus of schizophrenic subjects.

Previous studies have indicated a marked increase in the dopamine/norepinephrine ratio in thalami of schizophrenic patients compared with those of control subjects. Since these results all came from patients who were receiving neuroleptic drugs, the possibility exists that the increased dopamine concentrations are an effect of medication. To address this question, similar analyses were done on thalami from Huntington's Disease patients who had received neuroleptic treatment. The results showed no differences between the thalami of Huntington's Disease patients and controls, strongly suggesting that chronic treatment with neuroleptic drugs does not result in an increase of endogenous dopamine in the thalami of human subjects.