Tardive dyskinesia is caused by maladaptive synaptic plasticity: A hypothesis

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.

Transcranial direct current stimulation improves tardive dyskinesia in long-term hospitalized patients with chronic schizophrenia

OBJECTIVE

This study aimed to evaluate the efficacy and safety of transcranial direct current stimulation (tDCS) in chronic schizophrenia patients with tardive dyskinesia (TD) who were long-term hospitalized.

METHODS

Sixty-four inpatients who met the DSM-IV diagnostic criteria for schizophrenia and TD were randomly assigned to either the active (N=35) or sham (N=29) group. Treatment was given 15 times, with each session lasting for 30 min, and an intensity of 2 mA. The anode was placed on the left dorsolateral prefrontal cortex and the cathode on the right supraorbital region. Primary outcome was measured by the changes in Abnormal Involuntary Movements Scale (AIMS) score. Secondary outcomes were measured using the Positive and Negative Syndrome Scale (PANSS) and the Scale for the Assessment of Negative Symptoms (SANS). Adverse effects of tDCS were assessed with an experimenter-administered open-ended questionnaire throughout the experiment.

RESULTS

Of the 64 patients, 52 (81.25%) completed the study. Compared to the sham group, patients in the active group exhibited a significant reduction in both the total AIMS score and the facial-oral subscore (P<0.05). An improvement of at least 30% in total AIMS scores was observed in the active group (14 patients, 50%) compared to the sham group (2 patients, 8.3%) after treatment (P<0.01). There were no between-group differences in the PANSS and SANS total scores. However, there was a significant difference between the two groups in the occurrence of the reported adverse effect of tingling sensation (P<0.05).

CONCLUSIONS

TDCS may be an effective and safe treatment for improving the facial-oral motor symptoms of TD in chronically hospitalized patients with schizophrenia.

SIGNIFICANCE

This study provides a novel perspective for the clinical treatment of patients with TD.

A Case of Oral-Buccal-Lingual Dyskinesia and Neuropsychiatric Symptoms After Prolonged Levetiracetam Exposure

Tardive dyskinesia (TD) is a serious and often permanent complication usually seen after the long-term use of antipsychotic medications, and multiple other classes of medications have been reported to cause TD or TD-like syndromes. TD can affect any part of the body, but it most commonly affects the mouth, lips, and tongue. We present a case of oral-buccal-lingual dyskinesia in an 86-year-old female from the long-term use of levetiracetam for a seizure disorder. The patient was started on levetiracetam four years before admission and was noted to have an acute onset of oral-buccal-lingual dyskinesia that was so severe it interrupted the patient's speech and feeding. The patient's dyskinesias are completely resolved after cross-tapering levetiracetam 500 mg twice a day with valproic acid 750 mg daily. Additionally, there was a global recovery of the patient's mood and psychosis after the cross-taper. Our case highlights the potential implications of levetiracetam in dyskinetic movements and neuropsychiatric symptoms, and it warrants close monitoring of patients taking this medication especially elderly with multiple comorbidities and compromised renal function. Moreover, the case suggests the reversible nature of both neuropsychiatric symptoms and dyskinesias.

Comparative Analysis of Deutetrabenazine and Valbenazine as VMAT2 Inhibitors for Tardive Dyskinesia: A Systematic Review

Background

Tardive Dyskinesia (TD) is a neurological disorder characterized by involuntary movements, often caused by dopamine receptor antagonists. Vesicular Monoamine Transporter 2 (VMAT2) inhibitors, such as valbenazine and deutetrabenazine, have emerged as promising therapies for TD and several clinical trials have shown their efficacy. This study aims to compare the efficacy and safety profile of VMAT2 inhibitors, focusing on a recent trial conducted in the Asian population.

Methods

We reviewed the PubMed, Cochrane Library, Embase database, and clinicaltrials.gov between January 2017 and October 2023, using the keywords "tardive dyskinesia" AND ("valbenazine" [all fields] OR " deutetrabenazine " [all fields]) AND "clinical trial". The reviewed articles were studied for efficacy and side effects.

Results

An initial search yielded 230 articles, of which 104 were duplicates. Following the title and abstract screening, 25 additional articles were excluded. A full-text review resulted in the exclusion of 96 more articles. Ultimately, four double-blind clinical trials met the inclusion criteria. The deutetrabenazine studies demonstrated significant improvements in Abnormal Involuntary Movement Scale (AIMS) scores compared to placebo, with no difference in adverse events. The valbenazine studies showed favorable results in reducing TD symptoms and were well-tolerated.

Discussion

The studies reviewed in this analysis underscore the potential of deutetrabenazine and valbenazine as valuable treatment options for TD in diverse populations. Both medications demonstrated significant improvements in AIMS scores, suggesting their effectiveness in managing TD symptoms. Additionally, they exhibited favorable safety profiles, with low rates of serious adverse events and no significant increase in QT prolongation, parkinsonism, suicidal ideation, or mortality.

Conclusion

The studies reviewed highlight the promising efficacy and tolerability of deutetrabenazine and valbenazine as treatments for Tardive Dyskinesia, providing new hope for individuals affected by this challenging condition.

Management of Cholinergic Rebound After Abrupt Withdrawal of Clozapine: A Case Report and Systematic Literature Review

BACKGROUND

Cholinergic discontinuation symptoms, also known as "cholinergic rebound," from abrupt clozapine discontinuation are characterized by a range of somatic and psychiatric symptoms.

OBJECTIVE

The objective of this study was to describe the clinical features and management options for clozapine withdrawal-associated cholinergic rebound syndrome (henceforth referred to as CWCRS) and present an illustrative case report.

METHODS

Based on a literature search of the databases PubMed, OVID Medline, and Embase as well as reviewing reference lists of relevant past reviews, we carried out a systematic review of case reports on the management of CWCRS from 1946 to 2023.

RESULTS

We identified 10 previously published articles on the clinical management of CWCRS, with a total of 18 patients (6 female, 12 male) with an average age of 43 years (standard deviation 14). Half of the patients had a history of tardive dyskinesia. The mean dose of clozapine before discontinuation was 351 mg/day, with duration of clozapine treatment ranging from 3 weeks to 9 years. Clozapine was the most effective treatment, followed by benztropine.

CONCLUSIONS

Given the small number of cases and the nonexperimental nature of the available studies, this review could not provide reliable data to guide management of CWCRS. The findings, however, suggest that clozapine may be more effective than other commonly used treatment options. With the high rates of discontinuation among patients on clozapine, there is a pressing need for further research into the epidemiology, natural history, and management of clozapine withdrawal syndromes.

Dystonia and Parkinson's disease: Do they have a shared biology?

Parkinsonism and dystonia co-occur across many movement disorders and are most encountered in the setting of Parkinson's disease. Here we aim to explore the shared neurobiological underpinnings of dystonia and parkinsonism through the clinical lens of the conditions in which these movement disorders can be seen together. Foregrounding the discussion, we briefly review the circuits of the motor system and the neuroanatomical and neurophysiological aspects of motor control and highlight their relevance to the proposed pathophysiology of parkinsonism and dystonia. Insight into shared biology is then sought from dystonia occurring in PD and other forms of parkinsonism including those disorders in which both can be co-expressed simultaneously. We organize these within a biological schema along with important questions to be addressed in this space.

Deep Brain Stimulation in the Treatment of Tardive Dyskinesia

Tardive dyskinesia (TD) is a phenomenon observed following the predominantly long-term use of dopamine receptor blockers (antipsychotics) widely used in psychiatry. TD is a group of involuntary, irregular hyperkinetic movements, mainly in the muscles of the face, eyelid, lips, tongue, and cheeks, and less frequently in the limbs, neck, pelvis, and trunk. In some patients, TD takes on an extremely severe form, massively disrupting functioning and, moreover, causing stigmatization and suffering. Deep brain stimulation (DBS), a method used, among others, in Parkinson's disease, is also an effective treatment for TD and often becomes a method of last resort, especially in severe, drug-resistant forms. The group of TD patients who have undergone DBS is still very limited. The procedure is relatively new in TD, so the available reliable clinical studies are few and consist mainly of case reports. Unilateral and bilateral stimulation of two sites has proven efficacy in TD treatment. Most authors describe stimulation of the globus pallidus internus (GPi); less frequent descriptions involve the subthalamic nucleus (STN). In the present paper, we provide up-to-date information on the stimulation of both mentioned brain areas. We also compare the efficacy of the two methods by comparing the two available studies that included the largest groups of patients. Although GPi stimulation is more frequently described in literature, our analysis indicates comparable results (reduction of involuntary movements) with STN DBS.

Effects of cannabidiol on vacuous chewing movements, plasma glucose and oxidative stress indices in rats administered high dose risperidone

Atypical antipsychotics, despite their rapid dissociation from dopamine receptors and reduced tendency to induce oxidative stress, have been associated with difficult-to-manage movement disorders, including tardive dyskinesia (TD). The study set out to investigate the effects of cannabidiol (CBD), a potent antioxidant, on risperidone-induced behavioural and motor disturbances; namely vacuous chewing movements (VCM), and oxidative stress markers (e.g. superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), malondialdehyde (MDA), Nitric oxide (NO), and DPPH (2,2-diphenyl-1-picrylhydrazyl)). Oral risperidone (10 mg/kg) or oral CBD (5 mg/kg) were administered to six experimental groups. While risperidone alone was administered for 28 days, CBD concomitantly or in sequential order with risperidone, was administered for 28 days; and CBD alone was administered for 21 days. Behavioural, motor, and specific biochemical parameters, which included VCM, muscle tone, fasting blood sugar (FBS), and oxidative stress markers were assessed at different time points after the last dose of medication. Oral CBD (5 mg/kg) significantly reduced risperidone-induced elevated FBS when given after the administration of risperidone. Oral CBD also had effects on VCM when administered before risperidone and similarly, attenuated risperidone-induced increased muscle tone. It was also established that concomitant or sequential administration of CBD and risperidone did not have any adverse effects on cognition or locomotion. Both CBD and risperidone increased the activity of antioxidant enzymes and decreased the activity of pro-oxidant enzymes. This study suggests CBD could mitigate metabolic dysregulation and extrapyramidal side effects associated with risperidone without producing cognitive impairments.

The effects of cannabidiol on behavioural and oxidative stress parameters induced by prolonged haloperidol administration

OBJECTIVES

We investigated the influence of oral cannabidiol (CBD) on vacuous chewing movements (VCM) and oxidative stress parameters induced by short- and long-term administration of haloperidol in a rat model of tardive dyskinesia (TD).

METHODS

Haloperidol was administered either sub-chronically via the intraperitoneal (IP) route or chronically via the intramuscular (IM) route to six experimental groups only or in combination with CBD. VCM and oxidative stress parameters were assessed at different time points after the last dose of medication.

RESULTS

Oral CBD (5 mg/kg) attenuated the VCM produced by sub-chronic administration of haloperidol (5 mg/kg) but had minimal effects on the VCM produced by chronic administration of haloperidol (50 mg/kg). In both sub-chronic and chronic haloperidol groups, there were significant changes in brain antioxidant parameters compared with CBD only and the control groups. The sub-chronic haloperidol-only group had lower glutathione activity compared with sub-chronic haloperidol before CBD and the control groups; also, superoxide dismutase, catalase, and 2,2-diphenyl-1-picrylhydrazyl activities were increased in the sub-chronic (IP) haloperidol only group compared with the CBD only and control groups. Nitric oxide activity was increased in sub-chronic haloperidol-only group compared to the other groups; however, the chronic haloperidol group had increased malondialdehyde activity compared to the other groups.

CONCLUSIONS

Our findings indicate that CBD ameliorated VCM in the sub-chronic haloperidol group before CBD, but marginally in the chronic haloperidol group before CBD. There was increased antioxidant activity in the sub-chronic group compared to the chronic group.

Tardive Dyskinesia Development, Superoxide Dismutase Levels, and Relevant Genetic Polymorphisms

Tardive dyskinesia (TD) is a prevalent movement disorder that significantly impacts patients with schizophrenia (SCZ) due to extended exposure to antipsychotics (AP). Several genetic polymorphisms, including superoxide dismutase (SOD) and DRD3 9ser, have been suggested as explanations why some patients suffer from TD. Methods. A PubMed search was used to search relevant articles using the following keywords: “Tardive Dyskinesia and Superoxide Dismutase”. Fifty-eight articles were retrieved. Among them, 16 were included in this review. Results. Overall, 58 studies were retrieved from PubMed. Most studies investigated the association between TD and the SOD-related polymorphisms. In addition, previous studies reported an association between TD occurrence and other genetic polymorphisms. Conclusion. This study found that the risk of TD is associated with altered SOD levels and several genetic polymorphisms, including VAL 66 Met and DRD3 9ser.

Clinical Features, Neuroimaging, and Levodopa-Responsiveness in Holmes' Tremor: A Video-Based Case-Series with a Review of the Literature

BACKGROUND

Holmes' tremor (HT) is a low-frequency tremor characterized by a combination of rest, posture, and action components. We are reporting the clinical features, neuroimaging findings, and levodopa responsiveness in 12 patients with HT.

CASES

The majority of the patients were male (11/12). Dystonia was observed in 10 patients and the remaining two patients had head tremor, a "forme-fruste" of cervical dystonia. The underlying etiologies were vascular (n = 8), head trauma (n = 2), and tumor resection (n = 2). Neuroimaging showed isolated involvement of the midbrain in four, thalamus in two, and basal ganglia and cerebellum in one patient each. A combination of the lesion (thalamus and cerebellum = 2; cerebellopontine angle = 1, and cortical/subcortical = 1) was present in four patients. Levodopa responsiveness was seen in 75% of patients including one with levodopa-induced dyskinesia.

LITERATURE REVIEW

Of 139 patients from 49 studies, levodopa was tried in 123 patients. Improvement with levodopa was seen in 71 patients (57.72%). No improvement with levodopa was observed in 33 patients (26.82%) and details regarding therapeutic response were unavailable in 19 patients (15.44%).

CONCLUSIONS

Dystonia is an important clinical manifestation of HT. Levodopa responsiveness seen in the majority of the patients is consistent with the hypothesis that nigrostriatal pathway damage is crucial for the pathophysiology of HT.

Antipsychotic-induced supersensitivity - A reappraisal

OBJECTIVES

Tardive dyskinesia, psychotic relapse and treatment-refractory psychosis have long been associated. A common underlying mechanism involving antipsychotic-induced 'supersensitivity', albeit in different brain pathways, was proposed as early as 1978. This piece seeks to reappraise the concept and potential implications of antipsychotic-induced supersensitivity.

CONCLUSIONS

Evidence increasingly suggests that chronic antipsychotic exposure induces neuroadaptive physiological changes in dopaminergic, and other, neurotransmitter systems that may render some individuals more vulnerable to psychotic relapse - including those receiving continuous antipsychotic treatment. It is possible that in treating every episode of psychosis with prolonged or indefinite antipsychotic therapy, we paradoxically increase the risk of psychotic relapse in a significant proportion of people. A greater appreciation of supersensitivity may allow us to optimise any potential benefits of antipsychotics while minimising the risk of inadvertent iatrogenic harms. More research is needed to improve our understanding of the underlying neurophysiology of supersensitivity and to better identify which individuals are most vulnerable to its development. It is time we paid more attention to the concept, emerging evidence and potential implications of antipsychotic-induced supersensitivity and, where appropriate, adjusted our practice accordingly.

Differentiating tardive dyskinesia: a video-based review of antipsychotic-induced movement disorders in clinical practice

Accurate diagnosis and appropriate treatment of tardive dyskinesia (TD) are imperative, as its symptoms can be highly disruptive to both patients and their caregivers. Misdiagnosis can lead to incorrect interventions with suboptimal or even deleterious results. To aid in the identification and differentiation of TD in the psychiatric practice setting, we review its clinical features and movement phenomenology, as well as those of other antipsychotic-induced movement disorders, with accompanying links to illustrative videos. Exposure to dopamine receptor blocking agents (DRBAs) such as antipsychotics or antiemetics is associated with a spectrum of movement disorders including TD. The differential diagnosis of TD is based on history of DRBA exposure, recent discontinuation or dose reduction of a DRBA, and movement phenomenology. Common diagnostic challenges are the abnormal behaviors and dyskinesias associated with advanced age or chronic mental illness, and other movement disorders associated with DRBA therapy, such as akathisia, parkinsonian tremor, and tremor related to use of mood stabilizing agents (eg, lithium, divalproex). Duration of exposure may help rule out acute drug-induced syndromes such as acute dystonia or acute/subacute akathisia. Another important consideration is the potential for TD to present together with other drug-induced movement disorders (eg, parkinsonism, parkinsonian tremor, and postural tremor from mood stabilizers) in the same patient, which can complicate both diagnosis and management. After documentation of the phenomenology, severity, and distribution of TD movements, treatment options should be reviewed with the patient and caregivers.

Atypical dyskinesias under treatment with antipsychotic drugs: Report from the AMSP multicenter drug safety project

OBJECTIVES

The aim of this study was to describe atypical dyskinesias (AtypDs) occurring during treatment with antipsychotic drugs (APDs). AtypDs are dyskinesias showing either an unusual temporal relationship between onset of treatment and start of the adverse drug reaction (ADR) or an unusual presentation of clinical symptoms.

METHODS

Data on the utilisation of APDs and reports of severe APD-induced AtypDs were collected using data from the observational pharmacovigilance programme - 'Arzneimittelsicherheit in der Psychiatrie (English: drug safety in psychiatry)' (AMSP) - from 1993 to 2016.

RESULTS

A total of 495,615 patients were monitored, of which 333,175 were treated with APDs. Sixty-seven cases (0.020%) of severe AtypDs under treatment with APDs were registered. The diagnoses of schizophrenic disorders as well as organic mental disorders were related to significantly higher rates of AtypDs. Second-generation antipsychotic drugs (SGAs) showed slightly higher rates of AtypDs (0.024%) than high-potency (0.011%) or low-potency first-generation antipsychotic drugs (FGAs; 0.006%). In 41 cases (61.2%), two or more drugs were found to cause AtypDs.

CONCLUSIONS

Our study indicates that AtypDs are rare ADRs. SGAs may have a higher risk for the occurrence of AtypDs than FGAs. Clinicians should be aware of this ADR and patients should be monitored and examined carefully.

Case Report: Not All Neurological Symptoms Respond Well to Penicillin in Patients With Neurosyphilis

Patients with neurosyphilis present with a wide range of neurological symptoms, the response of which to penicillin is not well known. In this paper, we analyzed the clinical video-electroencephalogram (EEG) features of neurosyphilis in a 54-year-old man who exhibited with rhythmic orofacial involuntary movements, Argyll Robertson pupil, frequent paroxysmal oral-automatism seizures, periodic lateralized discharges (PLEDs) with triphasic waves, behavioral changes, and memory decline. After treatment with penicillin, PLED and seizures disappeared and behavioral changes and memory decline were significantly improved, but rhythmic orofacial involuntary movements and Argyll Robertson pupil persisted, which indicates an irreversible characteristic of late stage neurosyphilis syndromes.

VMAT2 Inhibitors for the Treatment of Tardive Dyskinesia

Psychiatric nurses are at the forefront of optimizing psychiatric care, including educating patients and caregivers on the risks of antipsychotic-induced movement disorders such as tardive dyskinesia (TD). Nurses should be aware that all patients taking antipsychotics should be regularly monitored for the development of TD. Given the current pandemic and increase in telehealth, assessing for TD is challenging; however, evaluation can be successfully completed by implementing the best practices described in this paper. Once TD is diagnosed, nurses can reassure patients that safe and effective FDA-approved treatments for TD (e.g., valbenazine) are now available.

Reflex memory theory of acquired involuntary motor and sensory disorders

Background

Explicit and implicit memories are conserved but flexible biological tools that nature uses to regulate the daily behaviors of human beings. An aberrant form of the implicit memory is presumed to exist and may be contributory to the pathophysiology of disorders such as tardive syndromes, phantom phenomena, flashback, posttraumatic stress disorders (PTSD), and related disorders. These disorders have posed significant clinical problems for both patients and physicians for centuries. All extant pathophysiological theories of these disorders have failed to provide basis for effective treatment.

Objective

The objective of this article is to propose an alternative pathophysiological theory that will hopefully lead to new treatment approaches.

Methods

The author sourced over 60 journal articles that treated topics on memory, and involuntary motor and sensory disorders, from open access journals using Google Scholar, and reviewed them and this helped in the formulation of this theory.

Results

From the reviews, the author thinks physical or chemical insult to the nervous system can cause defective circuit remodeling, leading to generation of a variant of implicit (automatic) memory, herein called “reflex memory” and this is encoded interoceptively to contribute to these phenomena states.

Conclusion

Acquired involuntary motor and sensory disorders are caused by defective circuit remodeling involving multiple neural mechanisms. Dysregulation of excitatory neurotransmitters, calcium overload, homeostatic failure, and neurotoxicity are implicated in the process. Sustained effects of these defective mechanisms are encoded interoceptively as abnormal memory in the neurons and the conscious manifestations are these disorders. Extant theories failed to recognize this possibility.

Spotlight on Oculogyric Crisis: A Review

BACKGROUND

Oculogyric crisis (OGC) is a form of acute dystonia characterized by sustained dystonic, conjugate, and upward deviation of the eyes. It was initially reported in patients with postencephalitic parkinsonism. But later, other factors such as medications, movement disorders, metabolic disorders, and focal brain lesions were also found to be associated with OGC.

METHODS

The literature regarding OGC was searched via PubMed, Google Scholar, and through citations in relevant articles till December 2019, with keywords including OGC, oculogyric eye movements, tonic eye movement, neuroleptics and OGC, antipsychotics and OGC, and all combinations of these. Only original articles (abstract or full text) that were published in the English language were reviewed.

RESULTS

Hypodopaminergic state is implicated in the pathogenesis of OGC. Common risk factors are younger age, male sex, severe illness, high neuroleptic dose, parenteral administration of neuroleptics, high potency of neuroleptic drugs, abrupt discontinuation of anticholinergic medication, and family history of dystonia.

CONCLUSION

OGC is an acute dystonic reaction leading to tonic upward deviation of eyes. It is associated with various neurometabolic, neurodegenerative, and movement disorders and medications such as antipsychotics, antiemetics, antidepressants, antiepileptics, and antimalarials. OGC can adversely impact the compliance and prognosis of the primary illness. Hence, it needs to be managed at earlier stages with appropriate medication, primarily anticholinergics.

Abnormal functional connectivity of motor circuit in the schizophrenic patients with tardive dyskinesia: A resting-state fMRI study

BACKGROUND

Animal and neuroimaging studies suggest that the volume of the motor-circuit region decreases in tardive dyskinesia (TD). This study examined the differences in functional connectivity within the motor circuit of patients with schizophrenia with and without TD to further clarify how the dysfunction is related to the pathogenesis of TD.

METHODS

Functional magnetic resonance images were taken of 56 schizophrenic patients with TD (TD group), 64 without TD (non-TD group), and 68 healthy controls (HC group). The motor-circuit area was selected as the seed region for a whole brain resting-state functional connectivity (rsFC) analysis. Psychopathological symptoms and TD severity were assessed with the Positive and Negative Syndrome Scale (PANSS) and Abnormal Involuntary Movement Scale (AIMS), respectively. Group differences and correlations among 18 brain regions of interest (e.g., the global strength of connectivity between two regions) were analyzed.

RESULTS

The analysis of variance results were as follows: The three groups exhibited rsFC losses in the left primary motor cortex, bilateral parietal cortices, right postcentral gyrus, right putamen, right superior parietal lobule, right supplementary motor area and bilateral thalami (false discovery rate,p < 0.05). The TD group showed a significant rsFC loss between the right postcentral gyrus and the inferior frontal gyrus of the left triangular part when compared with the non-TD group (AlphaSim, p < 0.001), which was negatively correlated with the AIMS total score (r=-0.259, p = 0.03).

CONCLUSIONS

These findings may suggest dysfunction of the postcentral and inferior frontal gyri of the triangular part in patients with schizophrenia and TD.

Tardive syndrome: An update and mini-review from the perspective of phenomenology

Tardive syndrome (TS) is a group of movement disorders caused by the long-term use of dopamine receptor blocking agents. The phenotypic presentation of TS is diverse, ranging from the most well-characterized symptom of tardive dyskinesia to other symptoms, including dystonia, akathisia, myoclonus, parkinsonism, tremor, and tics. These tardive symptoms are distinct not only in their phenomenology but also in their clinical outcomes. However, our knowledge of the pathophysiology and management of TS is almost exclusively based on tardive dyskinesia. First-generation antipsychotics have a higher risk of inducing TS and have largely been replaced by second-generation antipsychotics with a lower risk of TS. However, patients with off-label use of second-generation antipsychotics are still at risk of developing TS. Thus, the management of TS remains a challenging and important issue for physicians. In this review, we update the information on the epidemiology, phenomenology, and treatment of TS from the perspective of the specific form of TS.

Recent Advances in the Pharmacology of Tardive Dyskinesia

Tardive dyskinesia (TD) is a syndrome of abnormal involuntary movements that follows treatment with dopamine D2-receptor antagonists. Recent approval of vesicular monoamine transporter-2 (VMAT2) inhibitors offers hope for reducing the impact of TD. Although these drugs represent a significant advance in patient care and a practical step forward in providing relief for patients with TD, understanding of the pharmacology of TD that could inform future research to prevent and reverse TD remains incomplete. This review surveys evidence for the effectiveness of VMAT2 inhibitors and other agents in the context of theories of pathogenesis of TD. In patients for whom VMAT2 inhibitors are ineffective or intolerable, as well as for extending therapeutic options and insights regarding underlying mechanisms, a review of clinical trial results examined as experimental tests of etiologic hypotheses is worthwhile. There are still compelling reasons for further investigations of the pharmacology of TD, which could generate alternative preventive and potentially curative treatments. Finally, benefits from novel drugs are best realized within an overall treatment strategy addressing the condition and needs of individual patients.

Hyperkinetic manifestations in superficial siderosis: evidence for pathogenic network disruption

Superficial siderosis (SS) of central nervous system is a rare condition characterized by hemosiderin deposition diffusely involving supratentorial and infratentorial compartments. SS usually manifests with ataxia and sensorineural hearing loss. Basal ganglia are almost always spared by the degenerative process, and movement disorders are only rarely reported. We describe the case of an aged woman with apparently idiopathic SS presenting with cerebellar ataxia, hearing loss, and orofacial dyskinesias. Together with some previously reported patients affected by SS and presenting with dystonic manifestations, our case reinforces the current hypothesis supporting a wide network disruption, rather than a direct basal ganglia damage, as the likely underlying cause of some dystonic syndromes.

Investigation of the effects of cannabidiol on vacuous chewing movements, locomotion, oxidative stress and blood glucose in rats treated with oral haloperidol

Objectives: Tardive dyskinesia (TD) unlike acute dystonia may be irreversible. This study investigated the effects of oral cannabidiol (CBD) on haloperidol-induced vacuous chewing movement (VCM) model of TD. Methods: There were six experimental groups with different combinations of oral cannabidiol with 5 mg/kg of haloperidol given orally. Behavioural assays and FBS were measured. VCMs were assessed after the last dose of medication. Blood for oxidative stress assays was collected on the 8th day after the administration of the last dose of medication. Results: This study found that CBD co-administration with haloperidol attenuated the VCMs and increased motor tone produced by haloperidol. CBD alone at 5 mg/kg appears to have anxiolytic properties but may not be as effective as haloperidol which exhibited a greater anxiolytic effect at 5 mg/kg. Treatment with CBD alone at 5 mg/kg also appeared to enhance brain DPPH scavenging activity. Conclusions: We confirmed that CBD can ameliorate motor impairments produced by haloperidol. Our data suggest that CBD can be combined with haloperidol to prevent the emergent of extrapyramidal side effects and long-term movement disorders, such as acute dystonic disorder and TD.

Liver enzyme CYP2D6 gene and tardive dyskinesia

Background: Tardive dyskinesia (TD) is an iatrogenic involuntary movement disorder occurring after extended antipsychotic use with unclear pathogenesis. CYP2D6 is a liver enzyme involved in antipsychotic metabolism and a well-studied gene candidate for TD. Materials & methods: We tested predicted CYP2D6 metabolizer phenotype with TD occurrence and severity in our two samples of European chronic schizophrenia patients (total n = 198, of which 82 had TD). Results: TD occurrence were associated with extreme metabolizer phenotype, controlling for age and sex (p = 0.012). In other words, individuals with either increased and no CYP2D6 activity were at higher risk of having TD. Conclusion: Unlike most previous findings, TD occurrence may be associated with both extremes of CYP2D6 metabolic activity rather than solely for poor metabolizers.

Psychosis relapse during treatment with long-acting injectable antipsychotics in individuals with schizophrenia-spectrum disorders: an individual participant data meta-analysis

BACKGROUND

Most individuals with schizophrenia-spectrum disorders have relapses, which increase the risk of morbidity and mortality. Because non-adherence to antipsychotic maintenance treatment could affect more than half of individuals with schizophrenia-spectrum disorders, psychosis relapse can often be confounded by unnoticed treatment interruption. Research of relapse during confirmed antipsychotic exposure has basic clinical and neurobiological implications, but data are scarce. We aimed to generate reliable estimates of incidence and predictors of relapse during assured antipsychotic treatment.

METHODS

We did a systematic review and individual participant data (IPD) meta-analysis of clinical trials of long-acting injectable antipsychotics (LAIs) for psychosis relapse-prevention, following IPD-PRISMA guidelines. Datasets were identified by searching relevant repositories from inception to Aug 1, 2019. Each LAI group was reanalysed as a separate cohort, further identifying subcohorts of individuals with and without prospectively determined symptom remission (PSR). Summary incidence rate of relapse, incidence rate ratios (IRRs) of relapse between individuals with and without PSR, hazard ratios (HRs) of covariates on risk of relapse, and standardised mean difference (SMDs) in changes in overall functioning associated with relapse were generated by pooling results from the harmonised reanalysis of each study. This study is registered with PROSPERO, number CRD42019137439.

FINDINGS

19 treatment cohorts consisting of 5130 individuals (2938 with PSR, 2192 without PSR), with 3959·53 observed participant-years, were meta-analysed. Pooled incidence of relapse was 22·97 per 100 participant-years (14·76 per 100 participant-years for the PSR subcohort, 31·51 per 100 participant-years for the non-PSR subcohort), with an IRR of 0·19 (95% CI 0·07 to 0·54). Relapse was associated with functional decline (overall SMD -0·76, 95% CI -1·14 to -0·37; PSR SMD -0·52, 95% CI -0·80 to -0·21; non-PSR SMD -0·72, 95% CI -1·18 to -0·26). The strongest predictor of relapse was tardive dyskinesia at treatment onset (HR 2·39, 95% CI 1·05 to 5·42).

INTERPRETATION

Despite the established efficacy of antipsychotics in preventing relapse, these data indicate that these drugs might not prevent subsequent exacerbations for a proportion of individuals whose illness is stabilised on continuous antipsychotic treatment. Tardive dyskinesia in particular might have pathophysiological implications for relapse.

FUNDING

Northwell Health.

Tardive syndromes

Dopamine receptor-blocking antipsychotics, first introduced into clinical practice in 1952, were hailed as a panacea in the treatment of a number of psychiatric disorders. However, within 5 years, this notion was to be shattered by the recognition of both acute and chronic drug-induced movement disorders which can accompany their administration. Tardive syndromes, denoting the delayed onset of movement disorders following administration of dopamine receptor-blocking (and also other) drugs, have diverse manifestations ranging from the classic oro-bucco-lingual dyskinesia, through dystonic craniocervical and trunk posturing, to abnormal breathing patterns. Although tardive syndromes have been an important part of movement disorder clinical practice for over 60 years, their pathophysiologic basis remains poorly understood and the optimal treatment approach remains unclear. This review summarises the current knowledge relating to these syndromes and provides clinicians with pragmatic, clinically focused guidance to their management.

A unifying theory for the pathoetiologic mechanism of tardive dyskinesia

INTRODUCTION

Chronic treatment with dopamine D2 receptor antagonists has been proposed to lead to dopamine receptor supersensitivity. Frequently, this is conceptualized as upregulation or changes in the structure or function of the post-synaptic D2 receptor. However, the measured 1.4-fold increase in D2 receptor density and the lack of actual receptor supersensitivity are probably inadequate to explain outcomes such as tardive dyskinesia (TD) and dopamine supersensitivity psychosis.

HYPOTHESIS

Recent data suggest that TD may result from a combination of presynaptic, synaptic, and postsynaptic changes.

DISCUSSION

Presynaptic increase in dopamine release occurs when super-therapeutic blockade of postsynaptic D2 receptors results in excess synaptic unbound dopamine which ultimately ends up being reuptaken by the presynaptic neuron through the dopamine transporter. The increased availability of recycled dopamine results in higher vesicular dopamine concentrations. Since the quantity of neurotransmitter released (known as quanta) is determined by the number of presynaptic neurotransmitter vesicles, the increase in the number (concentration) of dopamine molecules in the vesicles results in a higher concentration of synaptic dopamine with successive depolarization events. Synaptic changes such as the appearance of perforated synapses which is an early step in new synapse formation have been shown in animal models of TD. Finally, postsynaptic increases in D2 receptor expression without demonstration of increased sensitivity or potency has been demonstrated.

CONCLUSION

TD likely develops due to changes across the synapse and terminology such as 'dopamine receptor supersensitivity' can be misleading. 'Synaptic upregulation' may be a more correct term.

Influence of magnesium supplementation and L-type calcium channel blocker on haloperidol-induced movement disturbances

Haloperidol (Hal) is an antipsychotic related to movement disorders. Magnesium (Mg) showed benefits on orofacial dyskinesia (OD), suggesting its involvement with N-methyl-D-aspartate receptors (NMDAR) since it acts blocking calcium channels. Comparisons between nifedipine (NIF; a calcium channel blocker) and Mg were performed to establish the Mg mechanism. Male rats concomitantly received Hal and Mg or NIF for 28 days, and OD behaviors were weekly assessed. Both Mg and NIF decreased Hal-induced OD. Hal increased Ca²⁺-ATPase activity in the striatum, and Mg reversed it. In the cortex, both Mg and NIF decreased such activity. Dopaminergic and glutamatergic immunoreactivity were modified by Hal and treatments: i) in the cortex: Hal reduced D1R and D2R, increasing NMDAR immunoreactivity. Mg and NIF reversed this Hal influence on D1R and NMDAR, while only Mg reversed Hal effects on D2R levels; ii) in the striatum: Hal decreased D2R and increased NMDAR while Mg and NIF decreased D1R and reversed the Hal-induced decreasing D2R levels. Only Mg reversed the Hal-induced increasing NMDAR levels; iii) in the substantia nigra (SN): while Hal increased D1R, D2R, and NMDAR, both Mg and NIF reversed this influence on D2R, but only Mg reversed the Hal-influence on D1R levels. Only NIF reversed the Hal effects on NMDAR immunoreactivity. These findings allow us to propose that Mg may be useful to minimize Hal-induced movement disturbances. Mg molecular mechanism seems to be involved with a calcium channel blocker because the NIF group showed less expressive effects than the Mg group.

The spectrum of involuntary vocalizations in humans: A video atlas

In clinical practice, involuntary vocalizing behaviors are typically associated with Tourette syndrome and other tic disorders. However, they may also be encountered throughout the entire tenor of neuropsychiatry, movement disorders, and neurodevelopmental syndromes. Importantly, involuntary vocalizing behaviors may often constitute a predominant clinical sign, and, therefore, their early recognition and appropriate classification are necessary to guide diagnosis and treatment. Clinical literature and video-documented cases on the topic are surprisingly scarce. Here, we pooled data from 5 expert centers of movement disorders, with instructive video material to cover the entire range of involuntary vocalizations in humans. Medical literature was also reviewed to document the range of possible etiologies associated with the different types of vocalizing behaviors and to explore treatment options. We propose a phenomenological classification of involuntary vocalizations within different categorical domains, including (1) tics and tic-like vocalizations, (2) vocalizations as part of stereotypies, (3) vocalizations as part of dystonia or chorea, (4) continuous vocalizing behaviors such as groaning or grunting, (5) pathological laughter and crying, (6) vocalizations resembling physiological reflexes, and (7) other vocalizations, for example, those associated with exaggerated startle responses, as part of epilepsy and sleep-related phenomena. We provide comprehensive lists of their associated etiologies, including neurodevelopmental, neurodegenerative, neuroimmunological, and structural causes and clinical clues. We then expand on the pathophysiology of the different vocalizing behaviors and comment on available treatment options. Finally, we present an algorithmic approach that covers the wide range of involuntary vocalizations in humans, with the ultimate goal of improving diagnostic accuracy and guiding appropriate treatment. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Tardive Syndromes

PURPOSE OF REVIEW

This article reviews the history, nosology, clinical features, epidemiology, and treatment of tardive syndromes.

RECENT FINDINGS

The major advance in the field of tardive syndromes has been the development and US Food and Drug Administration (FDA) approval of two vesicular monoamine transporter type 2 inhibitors, valbenazine and deutetrabenazine, for treating tardive syndromes. These medications are derivatives of tetrabenazine and reduce dyskinetic movements by reducing dopamine stimulation. Treatment is not curative, and the medications reduce, or "mask," symptoms but presumably without adding to the long-term risk of increased involuntary movements believed to accrue from suppressive treatment with dopamine receptor-blocking drugs. A confounding advance has been the accumulation of data finding that second-generation antipsychotics, also known as atypical antipsychotics, may not be safer than first-generation antipsychotics in causing tardive syndromes. The public health risk of tardive syndromes may actually have increased as some second-generation antipsychotics, widely promoted to both doctors and patients, are increasingly used as antidepressants.

SUMMARY

Tardive syndromes remain a public health risk. Second-generation antipsychotics have not been proven to have less risk than first-generation drugs in causing tardive syndromes and are nevertheless being used more widely to treat depression, bipolar disease, and insomnia. Symptomatic treatment for tardive syndromes is available, although expensive.

Antipsychotics: Mechanisms underlying clinical response and side-effects and novel treatment approaches based on pathophysiology

Antipsychotic drugs are central to the treatment of schizophrenia and other psychotic disorders but are ineffective for some patients and associated with side-effects and nonadherence in others. We review the in vitro, pre-clinical, clinical and molecular imaging evidence on the mode of action of antipsychotics and their side-effects. This identifies the key role of striatal dopamine D2 receptor blockade for clinical response, but also for endocrine and motor side-effects, indicating a therapeutic window for D2 blockade. We consider how partial D2/3 receptor agonists fit within this framework, and the role of off-target effects of antipsychotics, particularly at serotonergic, histaminergic, cholinergic, and adrenergic receptors for efficacy and side-effects such as weight gain, sedation and dysphoria. We review the neurobiology of schizophrenia relevant to the mode of action of antipsychotics, and for the identification of new treatment targets. This shows elevated striatal dopamine synthesis and release capacity in dorsal regions of the striatum underlies the positive symptoms of psychosis and suggests reduced dopamine release in cortical regions contributes to cognitive and negative symptoms. Current drugs act downstream of the major dopamine abnormalities in schizophrenia, and potentially worsen cortical dopamine function. We consider new approaches including targeting dopamine synthesis and storage, autoreceptors, and trace amine receptors, and the cannabinoid, muscarinic, GABAergic and glutamatergic regulation of dopamine neurons, as well as post-synaptic modulation through phosphodiesterase inhibitors. Finally, we consider treatments for cognitive and negative symptoms such dopamine agonists, nicotinic agents and AMPA modulators before discussing immunological approaches which may be disease modifying. This article is part of the issue entitled 'Special Issue on Antipsychotics'.

Overcoming barriers to effective management of tardive dyskinesia

Tardive dyskinesia (TD) is a heterogeneous syndrome of involuntary hyperkinetic movements that is often persistent and occurs belatedly during treatment with antipsychotics. Recent approval of two dopamine-depleting analogs of tetrabenazine based on randomized controlled trials offers an evidence-based therapeutic approach to TD for the first time. These agents are optimally used within the context of a comprehensive approach to patient management that includes a practical screening and monitoring program, sensitive and specific criteria for the diagnosis of TD, awareness of the severity and impact of the disorder, informed discussions with patients and caregivers, and a rational basis for prescribing decisions about continued antipsychotic and adjunctive agents. Areas of limited or inconclusive data, bias and misunderstandings about key aspects, and neglect of training about TD in recent years contribute to barriers in providing effective care and promoting patient safety.

Tardive Dyskinesia After Aripiprazole Treatment That Improved With Tetrabenazine, Clozapine, and Botulinum Toxin

We report on a patient with tardive dyskinesia (TDK) treated with aripiprazole, a third-generation antipsychotic with partial D2 agonist-antagonist activity at both the dopamine and serotonin receptors. The patient’s condition improved with administration of a combination of tetrabenazine, botulinum toxin, and clozapine, which has previously not been used. We suggest that this treatment combination may have potential benefits for patients with TDK. After aripiprazole discontinuation, the patient was treated with clozapine (150 mg/day) and biperiden (8 mg/day). Due to a lack of improvement, we administered 300 units (intramuscularly; IM) of botulinum toxin into the paravertebral muscles every 3 months and 1,000 units IM every 4 months in addition to tetrabenazine (75 mg/day) and biperiden (8 mg/day). The patient stopped this treatment, at which point TDK reappeared. After starting a treatment regimen of clozapine (100 mg/day), tetrabenazine (75 mg/day), and botulinum toxin (300 units IM), the patient’s symptoms remitted.

Treatment of Tardive Dyskinesia: A General Overview with Focus on the Vesicular Monoamine Transporter 2 Inhibitors

Tardive dyskinesia (TD) encompasses the spectrum of iatrogenic hyperkinetic movement disorders following exposure to dopamine receptor-blocking agents (DRBAs). Despite the advent of atypical or second- and third-generation antipsychotics with a presumably lower risk of complications, TD remains a persistent and challenging problem. Prevention is the first step in mitigating the risk of TD, but early recognition, gradual withdrawal of offending medications, and appropriate treatment are also critical. As TD is often a persistent and troublesome disorder, specific antidyskinetic therapies are often needed for symptomatic relief. The vesicular monoamine transporter 2 (VMAT2) inhibitors, which include tetrabenazine, deutetrabenazine, and valbenazine, are considered the treatment of choice for most patients with TD. Deutetrabenazine-a deuterated version of tetrabenazine-and valbenazine, the purified parent product of one of the main tetrabenazine metabolites, are novel VMAT2 inhibitors and the only drugs to receive approval from the US FDA for the treatment of TD. VMAT2 inhibitors deplete presynaptic dopamine and reduce involuntary movements in many hyperkinetic movement disorders, particularly TD, Huntington disease, and Tourette syndrome. The active metabolites of the VMAT2 inhibitors have high affinity for VMAT2 and minimal off-target binding. Compared with tetrabenazine, deutetrabenazine and valbenazine have pharmacokinetic advantages that translate into less frequent dosing and better tolerability. However, no head-to-head studies have compared the various VMAT2 inhibitors. One of the major advantages of VMAT2 inhibitors over DRBAs, which are still being used by some clinicians in the treatment of some hyperkinetic disorders, including TD, is that they are not associated with the development of TD. We also briefly discuss other treatment options for TD, including amantadine, clonazepam, Gingko biloba, zolpidem, botulinum toxin, and deep brain stimulation. Treatment of TD and other drug-induced movement disorders must be individualized and based on the severity, phenomenology, potential side effects, and other factors discussed in this review.

Genetic study of neuregulin 1 and receptor tyrosine-protein kinase erbB-4 in tardive dyskinesia

OBJECTIVES

Tardive dyskinesia (TD) is a movement disorder that may develop as a side effect of antipsychotic medication. The aetiology underlying TD is unclear, but a number of mechanisms have been proposed.

METHODS

We investigated single-nucleotide polymorphisms (SNPs) in the genes coding for neuregulin-1 and erbB-4 receptor in our sample of 153 European schizophrenia patients for possible association with TD.

RESULTS

We found the ERBB4 rs839523 CC genotype to be associated with risk for TD occurrence and increased severity as measured by the Abnormal Involuntary Movement Scale (AIMS) (P = .003).

CONCLUSIONS

This study supports a role for the neuregulin signalling pathway in TD, although independent replications are warranted.

Changes in recruitment of motor cortex excitation and inhibition in patients with drug-induced tardive syndromes

OBJECTIVES

It has recently been suggested that drug-induced tardive syndromes (TS) might be due to maladaptive plasticity, which increases motor excitability in cerebral cortex and basal ganglia. In order to test this hypothesis, we performed the first measurements of cortical excitability in TS.

METHODS

Motor cortex excitability was examined using transcranial magnetic stimulation (TMS) in 22 TS patients and compared with that in 20 age and sex-matched healthy individuals. Resting and active motor threshold (RMT, AMT) and input-output curves (I/O curves) assessed corticospinal excitability. The duration of the contralateral silent period (cSP) at a range of stimulation intensities and ipsilateral silent period (iSP) were used as measures of inhibition.

RESULTS

There were no significant differences in RMT and AMT between patients and controls, although the input-output curves were significantly steeper in patients. The cSP (at different stimulus intensities) and iSP were both longer in the patients compared to the control group. However, most of this difference could be accounted for by increased recruitment of motor evoked potentials (MEPs) in patients.

CONCLUSION

TS is characterized by hyperexcitability of corticospinal output that might contribute to the lack of selectivity in muscle recruitment and contribute to excess involuntary movement. The findings are opposite to those in naturally-occurring hyperkinesia such as Sydenham's and Huntington's chorea, suggesting a fundamental difference in the pathophysiology.

Tardive dyskinesia update: treatment and management

The development of rational treatments for tardive dyskinesia has been held back by limitations to our understanding of its aetiology, which even now does not extend far beyond its association with centrally acting dopamine-blocking drugs. This article reviews briefly the major aetiological theories and addresses general management and specific treatment options. Primary prevention and early recognition remain the crucial management issues because, once the condition is established, there are no satisfactory treatments. The article considers two newly developed drugs, valbenazine and deutetrabenazine, in some detail as, although they are not yet licensed in Europe, they have largely been responsible for an upsurge in interest in tardive dyskinesia in the North American literature and are likely to be widely promoted in the future. Although possessed of undoubted benefits, the evidence suggests that these represent small steps rather than large leaps forward in treatment.

LEARNING OBJECTIVES

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DECLARATION OF INTEREST

D.C.O. is psychiatric commissioner on the Commission on Human Medicines, the UK drug regulator, and chair of its expert advisory group on CNS drugs. He is also a member of the psychiatry Scientific Advisory Group of the European Medicines Agency.

Dystonia

Dystonia is a neurological condition characterized by abnormal involuntary movements or postures owing to sustained or intermittent muscle contractions. Dystonia can be the manifesting neurological sign of many disorders, either in isolation (isolated dystonia) or with additional signs (combined dystonia). The main focus of this Primer is forms of isolated dystonia of idiopathic or genetic aetiology. These disorders differ in manifestations and severity but can affect all age groups and lead to substantial disability and impaired quality of life. The discovery of genes underlying the mendelian forms of isolated or combined dystonia has led to a better understanding of its pathophysiology. In some of the most common genetic dystonias, such as those caused by TOR1A, THAP1, GCH1 and KMT2B mutations, and idiopathic dystonia, these mechanisms include abnormalities in transcriptional regulation, striatal dopaminergic signalling and synaptic plasticity and a loss of inhibition at neuronal circuits. The diagnosis of dystonia is largely based on clinical signs, and the diagnosis and aetiological definition of this disorder remain a challenge. Effective symptomatic treatments with pharmacological therapy (anticholinergics), intramuscular botulinum toxin injection and deep brain stimulation are available; however, future research will hopefully lead to reliable biomarkers, better treatments and cure of this disorder.

Decreased Gray Matter Volume of Cuneus and Lingual Gyrus in Schizophrenia Patients with Tardive Dyskinesia is Associated with Abnormal Involuntary Movement

Tardive dyskinesia (TD) is a devastating motor disorder associated with the etiological process of schizophrenia or antipsychotic medication treatments. To examine whether cerebral morphological changes may manifest in TD, we used voxel-based morphometry to analyze high-resolution T1-weighted brain structural magnetic resonance images from 32 schizophrenics with TD (TD group), 31 schizophrenics without TD (non-TD group), and 32 healthy controls (HC group). We also assessed psychopathological symptoms with the Positive and Negative Syndrome Scale (PANSS), and TD severity with the Abnormal Involuntary Movement Scale (AIMS). We compared gray matter volumes (GMVs) among groups, and tested for correlations between GMV changes and psychopathological symptoms or TD severity. The results showed significant differences in GMV in the frontal and temporal cortices, insula and cerebellum among the three groups. Brainstem and inferior frontal and precentral gyri GMVs were significantly larger, whereas cuneus and lingual gyrus GMVs were significantly smaller in the TD group as compared to non-TD group. Further, the cuneus and lingual gyrus GMVs were positively correlated with AIMS scores in the TD group. The current results suggest that TD may be associated with the alterations in GMV that are different from that of schizophrenics without TD. Further studies are needed to confirm and to examine the functional significance of these structural findings.