Gamma-Acetylenic GABA in tardive dyskinesia.

gamma-Acetylenic GABA, a drug that increases brain GABA via GABA transaminase inhibition, was evaluated in a blind placebo-controlled trial in 10 patients with stable tardive dyskinesia. Drug effects during active treatment (75 to 225 mg/day) and pre- and post-treatment placebo periods were determined by scoring TD and parkinsonian symptoms recorded weekly on videotape during standardized examinations. GAG significantly reduced TD (p < 0.01), although the effect was moderate, in patiens concurrently taking neuroleptics and increased preexisting parkinsonism. The greatest antihyperkinetic effects tended to occur in patients receiving higher neuroleptic doses, suggesting an interaction between GABA and dopamine. There was no effect of GAG on psychiatric symptoms. Further investigations with GAG and similar agents will be important tools for investigating GABA in movement disorders and other central nervous system dysfunctions.