Variable clinical response to choline in tardive dyskinesia.

Tardive dyskinesia is widely believed to be a state of relative hyperdopaminergic and hypocholinergic imbalance in the striatum of patients chronically treated with neuroleptics. However, not all patients with tardive dyskinesia respond to cholinergic drugs, which theoretically should restore the balance and improve the symptoms. We report a controlled, double-blind, crossover study of choline chloride in 11 patients with persistent tardive dyskinesia. Seven patients showed partial or minimal improvement, while two did not change and two deteriorated. The results are discussed in the light of other similar findings in the literature, and the implications for pharmacological subtypes of tardive dyskinesia using cholinergic probes are explored.