Eight poorly reported studies were included in an update of a Cochrane review . Patients with schizophrenia or other chronic mental illnesses with signs of antipsychotic-induced TD were included. For the outcome of ’no clinically important improvement in tardive dyskinesia’ GABA agonist drugs were not clearly better than placebo (n = 108, RR 0.83 CI 0.6 to 1.1). Deterioration in mental state was more likely to occur in people receiving GABA medication (n = 95, RR 2.47 CI 1.1 to 5.4). There is a suggestion of an increase in ataxia (loss of power of muscular coordination) for both baclofen and sodium valproate (n = 95, RR 3.26 CI 0.4 to 30.2), and in sedation (n = 113, RR 2.12 CI 0.8 to 5.4) compared with placebo, but this was not significant.
Comment: The quality of evidence is downgraded by study quality (inadequate allocation concealment), imprecise results (limited study size for each comparison).