Improvement in tardive dyskinesia after muscimol therapy.

Muscimol, thought to be a agonist of gamma-aminobutyric acid (GABA), was administered to eight neuroleptic-free subjects with tardive dyskinesia. At oral dose levels from 5 to 9 mg, involuntary movements were consistently attenuated, usually in the absence of sedation. These results support the view that pharmacologic attempts to stimulate GABA-mediated synaptic transmission may afford symptomatic relief to patients with tardive dyskinesia.