Pathophysiology, prognosis and treatment of tardive dyskinesia

A tardive dyskinesia drug target VMAT-2 participates in neuronal process elongation

Tardive dyskinesia involves involuntary movements of body parts and is often observed in individuals taking antipsychotics for extended periods. Initial treatment strategies include reducing medication dosage, switching medications, or using drugs to suppress symptoms. One of the therapeutic targets for tardive dyskinesia is vesicular monoamine transporter-2 (VMAT-2, also known as solute carrier family 18 member A2 [SLC18A2]), which functions as an energy-dependent transporter of monoamines. The therapeutic drugs are used during adulthood, when neurons are maturing. For the first time, we report that treatment with a chemical VMAT-2 inhibitor reduces neuronal process elongation, a phenomenon commonly observed during development. Treatment with the inhibitors reserpine or tetrabenazine decreased process elongation in primary cortical neurons, and similar results were obtained in N1E-115 neuronal model cells undergoing process elongation. Knockdown of VMAT-2 using clustered regularly interspaced short palindromic repeat (CRISPR)/Cas13-fitted guide RNA also reduced process elongation. However, treatment with reserpine or tetrabenazine did not affect the morphology of mature processes. Notably, treatment with hesperetin, a citrus flavonoid with neuroprotective effects, was able to restore the reduced process elongation induced by these inhibitors or VMAT-2 knockdown. The underlying molecular mechanism appeared to involve neuronal differentiation-related Akt kinase signaling. These results suggest that VMAT-2, as a drug target for tardive dyskinesia, plays a key role in process elongation and that some inhibitory effects of VMAT-2-targeted drugs on its elongation may be mitigated by co-administering a neuroprotective molecule.

Molecular and Behavioral Neuroprotective Effects of Clavulanic Acid and Crocin in Haloperidol-Induced Tardive Dyskinesia in Rats

Clavulanic acid (ClvA), a beta-lactamase inhibitor, is being explored for its significant neuroprotective potential. The effects of ClvA were assessed both individually and in combination with crocin (Cr), an antioxidant derived from saffron, in the context of tardive dyskinesia (TD). In rat haloperidol (Hp)-induced-TD (1 mg/kg, i.p. 21 days), the effects of ClvA (50, 100, 150 mg/kg) and Cr (10, 20, 40 mg/kg) were assessed via vacuous chewing movements (VCM) and tongue protrusion (TP). Striatal malondialdehyde (MDA) and glutathione (GSH) were measured spectrophotometrically. Based on the results, ClvA (100 mg/kg) and Cr (10 mg/kg) were determined with sub-effective doses. Glutamate transporter-subtype1 (GLT1), dopamine active transporter (DAT), vesicular monoamine transporter-type2 (VMAT2), Bax/Bcl2, cleaved Caspase3, phosphorylated AKT/AKT, IL1β, and TNFα levels were quantified using western blotting in sub-effective doses and their combination. The behavioral results of catalepsy and orofacial dyskinesia demonstrated model establishment. Hp decreased GLT1 (p < 0.05), DAT (p < 0.01), VMAT2 (p < 0.001), GSH and pAKT/AKT (p < 0.0001); increased TNFα (p < 0.05), IL1β, cleaved Caspase3 (p < 0.001); MDA and Bax/Bcl2 (p < 0.0001). ClvA 100 mg/kg reversed the decreased GLT1 and VMAT2 (p < 0.01), alongside the increased MDA (p < 0.0001) and VCM (p < 0.05). It also increased AKT phosphorylation (p < 0.05). No effects were noted on DAT, GSH, Bax/Bcl2, or inflammatory factors. However, the combination with Cr at 10 mg/kg influenced ClvA on DAT (p < 0.01) and resulted in a significant increase in GSH (p < 0.0001). Additionally, there was a marked decrease in TNFα (p < 0.0001) and IL1β (p < 0.001), enhancing its effects on reducing MDA and increasing pAKT/AKT (p < 0.0001). The combination adversely affected GLT1. ClvA protects against TD via GLT1 and VMAT2; combined with Cr, it enhances antioxidant effects, improves DAT, and requires dose optimization for GLT1 disruption.

Movement Disorders Associated with Levosulpiride: A Systematic Review of Prevalence, Risk Factors, and Therapeutic Approaches

REGISTRATION NUMBER

PROSPERO: CRD42024553156.

Second-generation antipsychotic-induced dystonia: Analysis using the Japanese Adverse Drug Event Report (JADER) database

AIM

This study aimed to explore the comparative risks for dystonia among different second-generation antipsychotics (SGAs), the influence of sex, and the relationship between the time-to-onset of dystonia and its outcomes.

METHODS

We analyzed data from the Japanese Adverse Drug Event Report database from April 2004 to November 2023. Cases involving oral SGAs, excluding clozapine, were extracted. We used the odds ratios to assess the reporting proportions among SGAs and sex, analyzed the median time-to-onset and interquartile ranges (IQRs), and conducted a receiver operating characteristic (ROC) curve analysis to investigate the time-to-onset of dystonia and its relationship to outcomes.

RESULTS

We extracted 9837 cases involving oral SGAs. Lurasidone was associated with a significantly higher proportion of dystonia reports than risperidone, aripiprazole, quetiapine, and olanzapine. The reporting proportion of dystonia associated with aripiprazole was lower than that of paliperidone and risperidone, but higher than that of quetiapine and olanzapine. Female sex was significantly associated with a higher reporting proportion of dystonia compared with males. Among the 148 cases of oral SGA-induced dystonia, the median time-to-onset was 125 days (IQR, 19.75-453.25 days). Divided into the three outcome groups (recovered, improved, and unrecovered/residual), those with better outcomes had a shorter time-to-onset than those with poorer outcomes. ROC curve analysis suggested a threshold of 91.5 days for discriminating outcomes, with a sensitivity of 71.7% and specificity of 69.9%.

CONCLUSIONS

The risks of dystonia may vary among SGAs and between sexes. SGA-induced dystonia often manifests in the tardive form.

Tardive Syndromes: A Challenging Multitude of Maladies

"Tardive syndrome" is an umbrella term for a group of drug-induced movement disorders associated with the prolonged use of mainly dopamine receptor blockers and also other medications. Early recognition followed by gradual withdrawal of the incriminating drug may lead to reversal, although not in all patients. Tardive syndromes are usually mixed movement disorders, with specific phenotypes, which may lead to severe disability. The pathophysiology remains incompletely understood. Treatment ranges from medical options, particularly dopamine-depleting agents and chemodenervation (botulinum toxin), to surgical options (deep brain stimulation and lesioning surgeries). Most studies that focused on treatment are limited by small patient numbers. Unfortunately, tardive syndromes often remain under-recognized in clinical practice. This article reviews the historical aspects, epidemiology and risk factors, pathophysiology, diagnostic criteria, clinical phenotypes, and management of tardive syndromes.

Electrophysiological Alterations in the Progression of Parkinson's Disease and the Therapeutic Effect of Tetrabenazine on Rats With Levodopa-Induced Dyskinesia

AIMS

Dopamine replacement therapy is the backbone of Parkinson's disease (PD) treatment. However, long-term levodopa (L-DOPA) administration can lead to the severely disabling motor complication L-DOPA-induced dyskinesia (LID), for which standard, effective therapy is currently lacking. This study was conducted to characterize the distinct neural electrophysiological patterns involved in the progression of PD and to examine the efficacy of tetrabenazine, a vesicular monoamine transporter-2 inhibitor, in alleviating dyskinesia and its underlying electrophysiological mechanism.

METHODS

Electrophysiological analysis was performed to obtain power spectrum density and functional connectivity information from local field potential (LFP) data recorded from the primary motor cortex (M1) and dorsolateral striatum (DLS) during different pathological states in PD model rats. Behavioral tests and abnormal involuntary movements (AIMs) scoring were conducted to confirm PD model establishment and assess LID severity.

RESULTS

Increased beta oscillations and abnormally strengthened beta causality in the M1 → DLS direction and exaggerated beta-band M1-DLS functional connectivity were observed in the PD state. L-DOPA administration suppressed beta activity and augmented gamma power in the M1 and DLS, with increased gamma causality in the M1 → DLS direction and beta causality in the DLS → M1 direction, as well as elevated gamma-band M1-DLS functional connectivity. Tetrabenazine strongly ameliorated dyskinetic manifestations. It suppressed gamma power in the M1 and DLS, reduced gamma causality and increased beta causality in the M1 → DLS direction, reduced beta causality in the DLS → M1 direction, and reduced gamma-band M1-DLS functional connectivity.

CONCLUSION

Tetrabenazine abrogated aberrant gamma activity to improve LID symptoms, which provides compelling evidence for its future clinical application in LID therapy.

Successful Electroconvulsive Therapy for Tardive Dyskinesia and Tardive Dystonia Refractory to Valbenazine Treatment: A Case Report and Narrative Literature Review

Tardive dyskinesia and dystonia are intractable extrapyramidal symptoms caused by the blockade of dopamine receptors by antipsychotic drugs. In addition to the reduction or discontinuation of the causative drug, valbenazine for tardive dyskinesia and botulinum toxin for tardive dystonia have been reported to be effective. However, their efficacy has not been fully demonstrated. In this study, we report the case of a female patient with bipolar disorder, valbenazine-resistant tardive dystonia, and tardive dyskinesia who achieved improvement in extrapyramidal symptoms with electroconvulsive therapy. Additionally, we conducted a narrative literature review on the safety and efficacy of electroconvulsive therapy for tardive dyskinesia and dystonia.

Brexpiprazole treatment for agitation in Alzheimer's dementia: A randomized study

INTRODUCTION

We evaluated the efficacy and safety of brexpiprazole for the treatment of agitation in Alzheimer's dementia (AAD) in Japanese patients.

METHODS

This was a phase 2/3 multicenter, randomized, double-blind, placebo-controlled, parallel-group study. Patients with AAD were randomized to receive brexpiprazole 1 mg/day or 2 mg/day, or placebo (3:4:4) for 10 weeks.

RESULTS

For the primary endpoint (change in Cohen-Mansfield Agitation Inventory [CMAI] total score from baseline to Week 10), both brexpiprazole 1 mg and 2 mg groups demonstrated statistically significant improvement versus placebo (2 mg: least squares [LS] mean difference -7.2 [95% confidence interval (CI): -10.0 to -4.3], p-value < 0.0001, 1 mg: LS mean difference -3.7 [95% CI: -6.8 to -0.7], p-value = 0.0175). The incidences of treatment-emergent adverse events reported in the brexpiprazole 1 mg, 2 mg, and placebo groups were 76.8%, 84.6%, and 73.8%, respectively.

DISCUSSION

Brexpiprazole 1 mg/day and 2 mg/day for 10 weeks was efficacious and well tolerated.

HIGHLIGHTS

Brexpiprazole treatment for 10 weeks improved agitation in Alzheimer's dementia. The efficacy of brexpiprazole 1 mg/day has been confirmed for the first time. The incidence of adverse events was higher compared to the previous studies. Both brexpiprazole 1 mg/day and 2 mg/day were generally well tolerated.

Profiling deutetrabenazine extended-release tablets for tardive dyskinesia and chorea associated with Huntington's disease

INTRODUCTION

Tardive dyskinesia (TD) and Huntington's disease (HD)-associated chorea are persistent and disabling hyperkinetic disorders that can be treated with vesicular monoamine transporter type 2 (VMAT2) inhibitors, including the recently approved once-daily (QD) formulation of deutetrabenazine (DTBZ ER). While its efficacy and safety profile have not been directly investigated, currently available data confirms bioequivalence and similar bioavailability to the twice-daily formulation (DTBZ BID).

AREAS COVERED

The authors briefly review the pivotal trials establishing efficacy of DTBZ for TD and HD-associated chorea, the pharmacokinetic data for bioequivalence between QD and BID dosing of DTBZ, as well as dose proportionality evidence, titration recommendations, and safety profile for DTBZ ER.

EXPERT OPINION

Long-term data show that DTBZ is efficacious and well tolerated for the treatment of TD and HD-associated chorea. DTBZ ER likely demonstrates therapeutic equivalence with no new safety signals. Due to the lack of comparative clinical trial data, no evidence-based recommendation about choice of VMAT2 inhibitor or switching between VMAT2 inhibitors can be made about best practice. Ultimately, QD dosing may offer the chance of improved medication adherence, an important consideration in patients with complex treatment regimens and/or patients with cognitive decline.

A review on side effect management of second-generation antipsychotics to treat schizophrenia: a drug safety perspective

INTRODUCTION

Effective side effects management present a challenge in antipsychotic treatment with second-generation antipsychotics (SGAs). In recent years, most of the commonly used SGAs, except for clozapine, have been shown to differ only slightly in their effectiveness, but considerably regarding perceived side effects, safety profiles, and compatibility to preexisting medical conditions.

AREAS COVERED

The current state of available evidence on side-effect management in SGA treatment of patients with schizophrenia spectrum disorders (SSD) is reviewed. In addition, current guideline recommendations are summarized, highlighting evidence gaps.

EXPERT OPINION

SGA safety and side effects needs to be considered in treatment planning. Shared decision-making assistants (SDMA) can support patients, practitioners and relatives to orient their decisions toward avoiding side effects relevant to patients' adherence. Alongside general measures like psychosocial and psychotherapeutic care, switching to better tolerated SGAs can be considered a relatively safe strategy. By contrast, novel meta-analytical evidence emphasizes that dose reduction of SGAs can statistically increase the risk of relapse and other unfavorable outcomes. Further, depending on the type and severity of SGA-related side effects, specific treatments can be used to alleviate induced side effects (e.g. add-on metformin to reduce weight-gain). Finally, discontinuation should be reserved for acute emergencies.

An Evidence-Based Update on Anticholinergic Use for Drug-Induced Movement Disorders

Drug-induced movement disorders (DIMDs) are associated with use of dopamine receptor blocking agents (DRBAs), including antipsychotics. The most common forms are drug-induced parkinsonism (DIP), dystonia, akathisia, and tardive dyskinesia (TD). Although rare, neuroleptic malignant syndrome (NMS) is a potentially life-threatening consequence of DRBA exposure. Recommendations for anticholinergic use in patients with DIMDs were developed on the basis of a roundtable discussion with healthcare professionals with extensive expertise in DIMD management, along with a comprehensive literature review. The roundtable agreed that "extrapyramidal symptoms" is a non-specific term that encompasses a range of abnormal movements. As such, it contributes to a misconception that all DIMDs can be treated in the same way, potentially leading to the misuse and overprescribing of anticholinergics. DIMDs are neurobiologically and clinically distinct, with different treatment paradigms and varying levels of evidence for anticholinergic use. Whereas evidence indicates anticholinergics can be effective for DIP and dystonia, they are not recommended for TD, akathisia, or NMS; nor are they supported for preventing DIMDs except in individuals at high risk for acute dystonia. Anticholinergics may induce serious peripheral adverse effects (e.g., urinary retention) and central effects (e.g., impaired cognition), all of which can be highly concerning especially in older adults. Appropriate use of anticholinergics therefore requires careful consideration of the evidence for efficacy (e.g., supportive for DIP but not TD) and the risks for serious adverse events. If used, anticholinergic medications should be prescribed at the lowest effective dose and for limited periods of time. When discontinued, they should be tapered gradually.

Associations between Catechol-O-methyltransferase (COMT) polymorphisms and cognitive impairments, psychiatric symptoms and tardive dyskinesia in schizophrenia

INTRODUCTION

Catechol-O-methyltransferase (COMT) is a crucial enzyme involved in dopamine metabolism and has been implicated in the etiology of tardive dyskinesia (TD). We aimed to investigate the associations between COMT gene polymorphisms and the occurrence and severity of TD in a Chinese population, as well as the impact on the psychiatric symptoms and cognitive impairments observed in TD patients.

METHODS

A total of 216 chronic schizophrenia patients, including 59 TD patients and 157 NTD patients, were recruited for this study. Three SNPs of the COMT gene (rs4680, rs165599 and rs4818) were selected and genotyped using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). TD severity, psychopathology and cognitive functioning were assessed using the Abnormal Involuntary Movement Scale (AIMS), the Positive and Negative Syndrome Scale (PANSS) and the Repeated Battery for Assessment of Neuropsychological Status (RBANS), respectively.

RESULTS

In TD patients, total AIMs scores were higher in carriers of the rs4680 AA genotype than in carriers of the AG and GG genotypes (p = 0.01, 0.006), carriers of the rs4818 GC and CC genotypes had higher orofacial scores than in GG genotypes (p = 0.032, 0.002). In male TD patients, carriers of the rs165599 GA genotype scored lower in the extremities and trunk scores than AA genotype carriers (p = 0.015). Moreover, in male TD patients, COMT rs4818 was associated with cognition, since the C allele carriers had significantly higher immediate memory (p = 0.043) and verbal function (p = 0.040) scores than the G allele carriers. In addition, rs165599 genotype interacted with TD diagnosis on depressed factor (p = 0.031).

CONCLUSION

Within the Chinese population, COMT gene polymorphisms could potentially serve as biomarkers for the symptoms and prognosis of TD patients.

Tardive dyskinesia in Asia- current clinical practice and the role of neurologists in the care pathway

Tardive dyskinesia (TD) is a movement disorder that can arise as a side effect of treatment with dopamine receptor-blocking agents (DRBAs), including antipsychotic drugs (APDs) used to manage psychotic illnesses. Second-generation APDs (SGAs) are often preferred to first-generation drugs due to their lower propensity to cause TD, however many SGAs-treated patients still develop the condition. Although TD is a global health concern, evidence regarding the occurrence of TD and how it is managed in Asian countries is currently limited. This article reports the results of a systematic review of the published literature on TD focusing on its prevalence, types of patients, knowledge of the condition, causative factors, and usual treatment pathways in clinical practice in Asian countries. Epidemiological data suggest that the prevalence of TD is increasing globally due to an overall rise in APD use, contributing factors being polypharmacy with multiple APDs, the use of higher than necessary doses, and off-label use for non-psychotic indications. Although exact prevalence figures for TD in Asian countries are difficult to define, there is a similar pattern of rising APD use which will result in increasing numbers of TD patients in this region. These issues need to be addressed and strategies developed to minimize TD risk and manage this disabling condition which impacts patients' quality of life and daily functioning. To date, both research into TD has been predominantly psychiatry focused and the perspectives from neurologists regarding the clinical management of this challenging condition are scarce. However, neurologists have an essential role in managing the movement disorders manifestations that characterize TD. Optimum management of TD, therefore, should ideally involve collaboration between psychiatrists and neurologists in joint care pathways, wherever practical. Collaborative pathways are proposed in this article, and the challenges that will need to be addressed in Asian countries to improve the care of people with TD are highlighted, with a focus on the neurologist's viewpoint and the implications for the management of TD globally.

Bacillus Calmette-Guérin Vaccine Attenuates Haloperidol-Induced TD-like Behavioral and Neurochemical Alteration in Experimental Rats

Tardive dyskinesia (TD) is a hyperkinetic movement disorder that displays unusual involuntary movement along with orofacial dysfunction. It is predominantly associated with the long-term use of antipsychotic medications, particularly typical or first-generation antipsychotic drugs such as haloperidol. Oxidative stress, mitochondrial dysfunction, neuroinflammation, and apoptosis are major pathophysiological mechanisms of TD. The BCG vaccine has been reported to suppress inflammation, oxidative stress, and apoptosis and exert neuroprotection via several mechanisms. Our study aimed to confirm the neuroprotective effect of the BCG vaccine against haloperidol-induced TD-like symptoms in rats. The rats were given haloperidol (1 mg/kg, i.p.) for 21 days after 1 h single administration of the BCG vaccine (2 × 107 cfu). Various behavioral parameters for orofacial dyskinesia and locomotor activity were assessed on the 14th and 21st days after haloperidol injection. On the 22nd day, all rats were euthanized, and the striatum was isolated to estimate the biochemical, apoptotic, inflammatory, and neurotransmitter levels. The administration of the BCG vaccine reversed orofacial dyskinesia and improved motor function in regard to haloperidol-induced TD-like symptoms in rats. The BCG vaccine also enhanced the levels of antioxidant enzymes (SOD, GSH) and reduced prooxidants (MDA, nitrite) and pro-apoptotic markers (Cas-3, Cas-6, Cas-9) in rat brains. Besides this, BCG treatment also restored the neurotransmitter (DA, NE, 5-HT) levels and decreased the levels of HVA in the striatum. The study findings suggest that the BCG vaccine has antioxidant, antiapoptotic, and neuromodulatory properties that could be relevant in the management of TD.

Multiple therapies relieve long-term tardive dyskinesia in a patient with chronic schizophrenia: A case report

BACKGROUND

Tardive dyskinesia (TD) is a serious and disabling movement disorder; it impairs social function and quality of life and increases the mortality rate. TD is usually induced by the use of antipsychotic drugs; however, the underlying mechanism remains unclear. Pharmacotherapy of TD includes cholinergic drugs, benzodiazepines, ginkgo biloba extract (GBE), antioxidants, amantadine, propanolol, botulinum toxin, valbenazine, and deutetrabenazine, whereas the non-pharmacotherapy approach includes modified electroconvulsive therapy (MECT) and deep brain stimulation. We successfully treated a chronic schizophrenia patient with comorbid long-term severe TD using deutetrabenazine, clozapine, and MECT.

CASE SUMMARY

A 69-year-old woman who was diagnosed as having schizophrenia 16 years ago developed severe TD after 6-mo prescription of risperidone oral solution. Her TD symptoms did not resolve despite various treatments, such as GBE, vitamin E, trihexyphenidyl, promethazine, benzodiazepines, and switching to quetiapine and olanzapine. After admission, she was given deutetrabenazine 6 mg bid. Her buccal tremor was slightly resolved 3 d later; however, her tongue remained protruded and could not be retracted. Quetiapine was switched to clozapine on day 4, and the buccal tremor remarkably resolved, and the tongue could be retracted into the mouth from day 6 onward. After three sessions of MECT, the buccal tremor resolved further. Since then, she has been able to take a semifluid diet, and her quality of life improved remarkably during 6 mo of follow-up.

CONCLUSION

TD is a serious condition which could be caused by antipsychotic medications; however, the best strategy against TD is prevention and monitoring during using antipsychotics. For patients with TD caused by antipsychotic medication use, multiple measures should be considered like switching to clozapine, adjunction with deutetrabenazine, or even MECT.

Putative role of immune reactions in the mechanism of tardive dyskinesia

The term extrapyramidal disorders is most often used for conditions such as Parkinson's disease or Huntington's disease, but also refers to a group of extrapyramidal side effects of antipsychotics (EPS), such as tardive dyskinesia (TD). After a brief description of some clinical features of TD, this article summarizes the relatively scarce results of research on a possible link between mainly cytokine levels and TD. This data was found by systematically searching Pubmed and Embase. The limitations of these types of studies are a major obstacle to interpretation. After describing relevant aspects of the neuroinflammatory response and the neuroanatomical backgrounds of EPS, a new hypothesis for the origin of TD is presented with emphasis on dysfunctions in the striosomal compartment of the striatum and the dorsal diencephalic connection system (DDCS). It is postulated that (partly immunologically-induced) increase in oxidative stress and the dopamine-dependent immune response in classic TD proceed primarily via the DDCS, which itself is activated from evolutionarily older parts of the forebrain. Neuroinflammatory responses in the choroid plexus of the third ventricle may contribute due to its proximity to the habenula. It is concluded that direct evidence for a possible role of inflammatory processes in the mechanism of TD is still lacking because research on this is still too much of a niche, but there are indications that warrant further investigation.