Miscellaneous treatments for neuroleptic-induced tardive dyskinesia

Tardive dyskinesia is a disabling movement disorder associated with the prolonged use of neuroleptic medication. This review, one in a series examining the treatment of tardive dyskinesia, will cover miscellaneous treatments not covered elsewhere.

To determine whether the following interventions were associated with a reduction of neuroleptic induced tardive dyskinesia: botulin toxin, endorphin, essential fatty acid, EX11582A, ganglioside, insulin, lithium, naloxone, oestrogen, periactin, phenylalanine, piracetam, stepholidine, tryptophan, neurosurgery, or ECT.

The initial search of Biological Abstracts (1982-1995), The Cochrane Schizophrenia Group's Register (January 1996), EMBASE (1980-1995), LILACS (1982-1996), MEDLINE (1966-1995) and PsycLIT (1974-1995) was updated by searching Cochrane Schizophrenia Group's Register in July 2002. References of all relevant studies were searched for further trial citations. Principal authors of trials were contacted.

Studies were selected if they focused on people with schizophrenia or other chronic mental illnesses, with neuroleptic-induced tardive dyskinesia and compared the use of the interventions listed above versus placebo or no intervention.

Studies were reliably selected, quality assessed and data extracted. Data were excluded where more than 50% of participants in any group were lost to follow up. For binary outcomes a random effects risk ratio (RR) and its 95% confidence interval (CI) was calculated. Where possible, the weighted number needed to treat/harm statistic (NNT/H), and its 95% confidence interval (CI), was also calculated. For continuous outcomes, endpoint data were preferred to change data. Non-skewed data from valid scales were to have been synthesised using a weighted mean difference (WMD).

Fifty-seven references describing 37 different trials were identified by the search strategy. Seven of these were included, 27 excluded, and three await assessment. Ceruletide was not clearly more effective than placebo (n=132, 2 RCTs, RR not any improvement in tardive dyskinesia 0.82 CI 0.6 to 1.1). This also applied to gamma-linolenic acid, although data were sparse (n=16, 1 RCT, RR no clinical improvement 1.00 CI 0.7 to 1.5), oestrogen (n=12, 1 RCT, RR no clinically important improvement 1.2 CI 0.8 to 1.7), and lithium (n=11, 1 RCT, RR no clinically important improvement 1.39 CI 0.6 to 3.1). Phenylalanine may even be detrimental (n=18, 1 RCT, MD AIMS score 4.40 CI 1.16 to 7.64). One small study (n=20) found that insulin was more likely to produce a clinical improvement in tardive dyskinesia than placebo (RR no clinical improvement 0.5 CI 0.3 to 0.9, NNT 2 CI 1 to 5).

There is no strong evidence to support the everyday use of any of the agents included in this review. All results must be considered inconclusive and these compounds probably should only be used within the context of a well-designed evaluative study.