Gamma-aminobutyric acid agonists for neuroleptic-induced tardive dyskinesia

Treating schizophrenia: the quality of evidence behind treatment recommendations and how it can improve

OBJECTIVE

To assess the methodological and reporting quality of systematic reviews that comprise the American Psychiatric Association (APA) Practice Guideline for the Treatment of Patients with Schizophrenia and to determine the extent to which results from Cochrane systematic reviews published after guideline development would alter or confirm current recommendations.

PARTICIPANTS

Systematic reviews that underpinned recommendations in the APA guidelines and Cochrane systematic reviews.

MAIN OUTCOME

Three independent reviewers scored all systematic reviews referenced in the guideline for quality and reporting using AMSTAR and PRISMA checklist, respectively. Items in both tools were individually graded and compared to identify consistently low-performing areas within the systematic reviews. Post hoc analysis of the Cochrane systematic reviews since the latest revision of APA's guidelines were performed to determine whether their findings were congruent with recent recommendations.

RESULTS

The mean score of the 57 reviews on the PRISMA checklist was 70%. The mean AMSTAR score was 6.8, correlating with a moderate quality score. Post hoc analysis revealed that 171 Cochrane reviews had been published since the APA guideline release. Only half of the reviews of pharmacological interventions confirmed current recommendations.

CONCLUSIONS AND RELEVANCE

The methodological quality of the systematic reviews included in the APA guideline was deficient in key areas. Our study brings to light the importance of using high-quality evidence in the development of clinical practice guidelines. An updated APA guideline (last updated in 2009) is necessary to provide the highest quality treatment recommendations for clinicians in the management of schizophrenia.

TRIAL REGISTRATION NUMBER

UMIN-CTR, UMIN000023099.

Tardive dyskinesia (syndrome): Current concept and modern approaches to its management

Tardive dyskinesia is a serious, disabling and potentially permanent, neurological hyperkinetic movement disorder that occurs after months or years of taking psychotropic drugs. The pathophysiology of tardive dyskinesia is complex, multifactorial and still not fully understood. A number of drugs were tried for the management of this motor disturbance, yet until now no effective and standard treatment has been found. It is very disappointing to realize that the introduction of antipsychotics from the second generation has not significantly decreased the prevalence and incidence of tardive dyskinesia. Therefore, the management of this motor disturbance remains an actual topic as well as a challenge for clinicians. This review summarizes recent relevant publications concerning the treatment of tardive dyskinesia.

An update on tardive dyskinesia: from phenomenology to treatment

Tardive dyskinesia (TD), characterized by oro-buccal-lingual stereotypy, can manifest in the form of akathisia, dystonia, tics, tremor, chorea, or as a combination of different types of abnormal movements. In addition to movement disorders (including involuntary vocalizations), patients with TD may have a variety of sensory symptoms, such as urge to move (as in akathisia), paresthesias, and pain. TD is a form of tardive syndrome-a group of iatrogenic hyperkinetic and hypokinetic movement disorders caused by dopamine receptor-blocking agents. The pathophysiology of TD remains poorly understood, and treatment of this condition is often challenging. In this update, we provide the most current information on the history, nomenclature, etiology, pathophysiology, epidemiology, phenomenology, differential diagnosis, and treatment of TD.

Treatment of neurolept-induced tardive dyskinesia

Tardive dyskinesia (TDK) includes orobuccolingual movements and "piano-playing" movements of the limbs. It is a movement disorder of delayed onset that can occur in the setting of neuroleptic treatment as well as in other diseases and following treatment with other drugs. The specific pathophysiology resulting in TDK is still not completely understood but possible mechanisms include postsynaptic dopamine receptor hypersensitivity, abnormalities of striatal gamma-aminobutyric acid (GABA) neurons, and degeneration of striatal cholinergic interneurons. More recently, the theory of synaptic plasticity has been proposed. Considering these proposed mechanisms of disease, therapeutic interventions have attempted to manipulate dopamine, GABA, acetylcholine, norepinephrine and serotonin pathways and receptors. The data for the effectiveness of each class of drugs and the side effects were considered in turn.

Adjuvant use of nutritional and herbal medicines with antidepressants, mood stabilizers and benzodiazepines

Adjuvant use of nutritional and herbal medicines has potential to increase the efficacy of synthetic pharmaceuticals, and perhaps also decrease their side-effects by allowing lower doses to be prescribed. We evaluated current evidence for adjuvant use of nutritional and herbal medicines with antidepressants, mood stabilizers and benzodiazepines; and explored novel future areas of research. The paper also critiques current evidence for co-administration of St. John's wort with synthetic antidepressants. We performed a systematic search of MEDLINE, CINAHL, PsycINFO, The Cochrane database, China National Knowledge Infrastructure and the Chinese Science Citation Database. Search results were supplemented by a review of reference lists and a forward search using the Web of Science. Where possible we calculated effect sizes. Encouraging evidence exists for the use of omega-3 fatty acids, SAMe, folic acid and l-tryptophan adjuvantly with antidepressants to enhance response and improve efficacy. Various nutrients also have emerging evidence as effective adjuncts with antipsychotics and mood stabilizers. While some evidence supports nutritional adjuvancy with various psychopharmacotherapies, adjuvant use of herbal therapies has not been sufficiently studied to warrant standard clinical application. This remains a promising area of research via robust, safety-conscious studies.

Tardive Syndromes in the Elderly

Tardive syndromes are characterized by abnormal involuntary movements that occur after prolonged exposure to drugs that block dopamine receptors. The prevalence and incidence of tardive syndromes are much higher in elderly individuals, and the number of elderly patients receiving antipsychotics has been increasing. This article summarizes the clinical phenomenology, pathophysiology, epidemiology, and treatment of these disorders in elderly individuals.

Benzodiazepines for neuroleptic-induced tardive dyskinesia

BACKGROUND

Tardive dyskinesia (TD) is a disfiguring movement disorder, often of the orofacial region, frequently caused by the use of neuroleptic drugs. A wide range of strategies have been used to help manage tardive dyskinesia, and for those who are unable to have their antipsychotic medication stopped or substantially changed, the benzodiazepine group of drugs have been suggested as a useful adjunctive treatment.

OBJECTIVES

To determine the effects of benzodiazepines for neuroleptic-induced tardive dyskinesia in people with schizophrenia or other chronic mental illnesses.

SEARCH STRATEGY

1. Electronic searches. For the update of 2006, we searched The Cochrane Schizophrenia Group Trials Register (November 2005). For the previous two updates (1996, 2002) the review authors searched Biological Abstracts (1982-2002), the Cochrane Schizophrenia Group's Register of trials (February 2002), EMBASE (1980-2002), LILACS (1982-2002), MEDLINE (1966-2002), PsycLIT (1974-2002), SCISEARCH (2002), hand searched references of all included/excluded studies and contacted the first author of each included trial.

SELECTION CRITERIA

We included all randomised clinical studies focusing on people with schizophrenia (or other chronic mental illnesses) and neuroleptic-induced tardive dyskinesia that compared benzodiazepines with placebo or no intervention.

DATA COLLECTION AND ANALYSIS

We independently extracted data from the studies and ensured that they were reliably selected, and quality assessed. For homogenous dichotomous data we calculated random effects, relative risk (RR), 95% confidence intervals (CI) and, where appropriate, numbers needed to treat (NNT) on an intention-to-treat basis. We synthesised continuous data from valid scales by using a weighted mean difference (WMD). For continuous outcomes we preferred endpoint data to change data.

MAIN RESULTS

We identified three trials (total N=56, one additional trial since 2002, n=24). Using benzodiazepines as an adjunctive treatment did not result in any clear changes for a series of tardive dyskinesia medium-term outcomes (n=30, 2 RCTs, RR not improved to clinically important extent 1.08 CI 0.57 to 2.05). One trial (n=24) found end point abnormal movement scores to be better for those receiving adjunct benzodiazepines(WMD AIMS -3.22 CI -4.63 to -1.81 ). Less than 10% in both groups left these studies before completion and none of the studies reported clear adverse effects.

AUTHORS' CONCLUSIONS

One small study reports some preliminary evidence that benzodiazepines may have some effect in neuroleptic induced tardive dyskinesia. Inconclusive results from other studies means routine clinical use is not indicated and these treatments remain experimental.

The effects of eicosapentaenoic acid in tardive dyskinesia: a randomized, placebo-controlled trial

OBJECTIVE

Worldwide, conventional antipsychotic medication continues to be used extensively, and tardive dyskinesia (TD) remains a serious complication. The primary objective of the present study was to compare the efficacy of EPA versus placebo in reducing symptoms of TD.

METHOD

This was a 12-week, double-blinded, randomized study of ethyl-EPA 2g/day versus placebo as supplemental medication, in patients with schizophrenia or schizoaffective disorder, with established TD.

RESULTS

Eighty-four subjects were randomized, of whom 77 were included in the analysis. Both the EPA and placebo groups displayed significant baseline to endpoint improvements in Extrapyramidal Symptom Rating Scale dyskinesia scores, but there were no significant between-group differences (p=0.4). Response rates (>or=30% improvement in TD symptoms) also did not differ significantly between EPA-treated subjects (45%) and placebo-treated subjects (32%) (p=0.6). However, a post-hoc linear mixed model repeated measures analysis of variance indicated an effect for treatment group and duration of TD. The EPA-treated patients had significantly greater mean reductions in dyskinesia scores initially, although this was not sustained beyond 6 weeks.

CONCLUSIONS

This trial failed to demonstrate an anti-dyskinetic effect for ethyl-EPA 2g/day on the primary efficacy measure. However, a modest and transient benefit is suggested in patients with more recent onset of TD. The lack of clear-cut efficacy could be explained on the basis of the dose of EPA being too low, the study being underpowered, TD being too chronic in the majority of cases, differences in dietary fatty acid intake, or that EPA lacks an anti-dyskinetic action.

Prevalence of and risk factors for tardive dyskinesia in a Xhosa population in the Eastern Cape of South Africa

OBJECTIVE

Despite prolonged use of antipsychotic drug treatment, the prevalence of tardive dyskinesia (TD) in a Xhosa population has not been evaluated. This study was undertaken to assess the prevalence and identify possible factors, including antioxidant intake and smoking history, which may increase or reduce the risk of TD.

METHOD

One hundred two subjects who had been exposed to typical antipsychotic drugs for at least 6 months and were currently on an antipsychotic were screened for abnormal movements using the Abnormal Involuntary Movement Scale (AIMS) rating scale. Data about current and past antipsychotic therapy, diagnoses, smoking history, and dietary factors were gathered from the patient and from chart view.

RESULT

Twenty-eight and four-tenths percent of subjects met criteria for tardive dyskinesia. Years of treatment and total cumulative antipsychotic dose were significant predictors of TD. Subjects with higher total consumption of foods containing antioxidants had lower rates of TD, but only consumption of onions was significantly associated with reduced prevalence. TD was less prevalent in smokers, but this difference did not reach statistical significance. Age, sex, and psychiatric diagnosis did not predict presence of TD.

CONCLUSION

The result of this study indicate that TD in this population is more prevalent than previously believed within this local clinical context. Prolonged treatment and total antipsychotic drug exposure are important risk factors for TD in this population. Further study of the role of concurrent medications and dietary factors is indicated.

Effects of gabaergic drugs on reserpine-induced oral dyskinesia

Recently we have described the antidyskinetic property of the GABA mimetic drugs valproic acid and topiramate on reserpine-induced oral dyskinesia. In this respect, oral dyskinesia has been associated with important neuropathologies. The present study investigates the effects of different doses of the GABA(A) agonist tetrahydroisoxazolopyridine (THIP), of the GABA(B) agonist baclofen as well as of the GABA(A) modulator diazepam on the manifestation of reserpine-induced orofacial dyskinesia. Male Wistar rats received two injections of vehicle or of 1mg/kg reserpine separated by 48 h. Twenty-four hours later, animals were acutely treated with vehicle or THIP (2, 4 or 8 mg/kg), baclofen (1, 2 or 4 mg/kg) or diazepam (1, 2 or 4 mg/kg) and were observed for quantification of oral dyskinesia and open-field general activity. In order to verify the effects of these drugs per se on spontaneous oral movements, male Wistar rats were acutely treated with vehicle, 8 mg/kg THIP, 4 mg/kg baclofen or 4 mg/kg diazepam and observed for quantification of oral dyskinesia. The two highest doses of THIP or of baclofen abolished the manifestation of reserpine-induced oral dyskinesia while the lowest dose of baclofen attenuated it. Diazepam did not modify reserpine-induced oral dyskinesia at any dose tested. The highest doses of these drugs did not modify spontaneous oral movements. Reserpine-induced decrease in open-field general activity was not modified by any of the doses of THIP and diazepam or by the two lowest doses of baclofen. The highest dose of baclofen potentiated the increase in the duration of immobility induced by reserpine. These results reinforce the involvement of GABAergic hypofunction in the expression of oral dyskinesias, and support the potential therapeutic use of THIP and baclofen in the treatment of oral dyskinesias.

Effects of topiramate on oral dyskinesia induced by reserpine

Recently, we have described the antidyskinetic property of the GABA mimetic drug valproic acid on reserpine-induced oral dyskinesia, an animal model that has been related to tardive as well as acute dyskinesias, which are associated with important neuropathologies. The present study investigates the effects of different doses of the GABA mimetic anticonvulsant topiramate on the manifestation of reserpine-induced orofacial dyskinesia. Female EPM-M1 mice received two injections of control solution or of 0.5 mg/kg reserpine separated by 48 h. Twenty-four hours after the second reserpine or control solution injection, animals were acutely treated with control solution or topiramate (1, 3, 10 or 30 mg/kg) and were observed for quantification of oral dyskinesia or general activity in an open-field. In order to verify the effects of topiramate per se on oral dyskinesia or general activity, female EPM-M1 mice were acutely treated with control solution or 1, 3, 10 or 30 mg/kg topiramate and observed for quantification of oral dyskinesia and general activity. The highest dose of topiramate completely abolished the manifestation of reserpine-induced oral dyskinesia whereas the doses of 3 and 10 mg/kg significantly attenuated it. None of the doses of the anticonvulsant modified spontaneous locomotion frequency or oral movements, whereas spontaneous rearing frequency was decreased by 3, 10 and 30 mg/kg topiramate. The highest dose of topiramate did not modify general activity in reserpine-treated mice. These results support the potential therapeutic use of topiramate in the treatment of oral dyskinesias.

Calcium channel blockers for neuroleptic-induced tardive dyskinesia

BACKGROUND

Tardive dyskinesia is a disfiguring movement disorder of the orofacial region often caused by antipsychotic drugs. A wide range of strategies has been used to help manage tardive dyskinesia and, for people who are unable to have their antipsychotic medication stopped or substantially changed, the calcium-channel blocking group of drugs (diltiazem, nifedipine, nimodipine, verapamil) has been suggested as a useful adjunctive treatment.

OBJECTIVES

To determine the effects of calcium-channel blocker drugs (diltiazem, nifedipine, nimodipine, verapamil) for treatment of neuroleptic-induced tardive dyskinesia in people with schizophrenia, schizoaffective disorder or other chronic mental illnesses.

SEARCH STRATEGY

We updated previous searches of the Cochrane Schizophrenia Group Register (1982-2000), Cochrane Library (Issue 4, 2000), Cochrane Schizophrenia Group's register of trials (November 2000), EMBASE (1980-2000), LILACS (1982-2000), MEDLINE (1966-2000), PsycLIT (1974-2000), and SCISEARCH by searching the Cochrane Schizophrenia Group Register (September 2003). We searched references of all identified studies for further trial citations and contacted authors of trials.

SELECTION CRITERIA

Randomised clinical trials comparing calcium-channel blockers to placebo or no intervention for people with both tardive dyskinesia and schizophrenia or serious mental illness.

DATA COLLECTION AND ANALYSIS

Data were to have been independently extracted and analysed on an intention-to-treat basis. The relative risk (RR) and 95% confidence intervals (CI) of homogeneous dichotomous data were to have been calculated using a random effects model, and, where possible, the number needed to treat calculated. Weighted mean differences (WMD) were to have been calculated for continuous data.

MAIN RESULTS

No trials were included. We excluded fourteen studies; eight were not randomised, one did not use calcium channel blockers and five small, randomised, studies reported no usable data.

REVIEWER'S CONCLUSIONS

The effects of calcium-channel blockers for antipsychotic induced tardive dyskinesia are unknown. Their use is experimental and should only be given in the context of well designed randomised studies.

Effects of valproic acid on an animal model of tardive dyskinesia

GABAergic hypofunction in the basal ganglia is stated as an important mechanism underlying the pathophysiology of tardive dyskinesia. The present study investigates the effects of the GABA-mimetic drug valproic acid (VA) on the manifestation of reserpine-induced orofacial movements, an animal model of tardive dyskinesia. Male Wistar rats received two injections of control solution or of 1 mg/kg reserpine separated by 48 h. Twenty-four hours later, animals were acutely treated with 50, 100, or 200 mg/kg VA or control solution and were observed for quantification of orofacial movements and of open-field general activity. The highest dose of VA inhibited the manifestation of reserpine-induced orofacial movements but none of the VA doses modified reserpine-induced decrease in open-field general activity. These results support the potential of VA as an effective pharmacological tool in the treatment of tardive dyskinesia.

Cholinergic medication for neuroleptic-induced tardive dyskinesia

BACKGROUND

Tardive dyskinesia remains a troublesome adverse effect of conventional antipsychotic (neuroleptic) medication. It has been proposed that tardive dyskinesia could have a component of central cholinergic deficiency. Cholinergic drugs have been used to treat tardive dyskinesia.

OBJECTIVES

To determine the effects of cholinergic drugs (arecoline, choline, deanol, lecithin, meclofenoxate, physostigmine, RS 86, tacrine, metoxytacrine, galantamine, ipidacrine, donepezil, rivastigmine, eptastigmine, metrifonate, xanomeline, cevimeline) for treating neuroleptic-induced tardive dyskinesia in people with schizophrenia or other chronic mental illness.

SEARCH STRATEGY

An electronic search of the Cochrane Schizophrenia Group's register (October 2001) was undertaken. This register is assembled by extensive searches for randomised controlled trials in many electronic databases, registers of conference proceedings and dissertations. References of all identified studies were searched for further trial citations. Principal authors of trials were contacted.

SELECTION CRITERIA

Reports identified by the search were included if they were of controlled trials dealing with people with neuroleptic-induced tardive dyskinesia and chronic mental illness, who had been randomly allocated to either a cholinergic agent or to a placebo or no intervention. Two reviewers independently assessed methodological quality of trials.

DATA COLLECTION AND ANALYSIS

Two researchers extracted data and, where possible, estimated relative risks (RR) or weighted mean differences (WMD), with 95% confidence intervals (CI). Data were analysed on an intention-to-treat basis, with the assumption that people who dropped out had no improvement.

MAIN RESULTS

We included eleven studies investigating the use of older cholinergic drugs compared with placebo. Most studies involved small numbers of participants (5-20 people). We found no completed trials of the new cholinergic Alzheimer drugs for the treatment of tardive dyskinesia. Cholinergic drugs did not result in any substantial improvement in tardive dyskinesia symptoms when compared with placebo (8 RCTs, 170 people, RR no important improvement 0.84 CI 0.68 to 1.04). Neither did tardive dyskinesia symptoms increase (7 RCTs, 137 people, RR deterioration in tardive dyskinesia 1.17 CI 0.55 to 2.50). Pooled results for endpoint AIMS scores were equivocal (4 RCTs, 86 people, WMD -0.19 CI -0.53 to 0.14). Deanol may cause gastric adverse effects (5 RCTs, 61 people, RR 9.00 CI 0.55-148) and other adverse effects such as sedation and peripheral cholinergic effects (6 RCTs, 94 people, RR 6.83 CI 0.99-47). One study reported on global outcome. Meclofenoxate was neither clearly helpful nor harmful when compared with placebo (1 RCT, 60 people, RR not of global benefit 0.89 CI 0.59 to 1.32). We found no difference between people allocated cholinergics and those given placebo for the outcome of leaving the study before completion (10 RCTs, 240 people, RR 0.52 CI 0.21 to 1.33).

REVIEWER'S CONCLUSIONS

Tardive dyskinesia remains a major public health problem. The clinical effects of older cholinergic drugs are unclear, as too few, too small studies leave many questions unanswered. Cholinergic drugs should remain of interest to researchers and currently have little place in routine clinical work. However, with the advent of new cholinergic agents now used for treating Alzheimer's disease, scope exists for more informative trials. If these new cholinergic agents are to be investigated for treating people with tardive dyskinesia, their effects should be demonstrated in well-designed, conducted and reported randomised trials.