Antipsychotic drug-induced movement disorders

Movement disorders of the mouth: a review of the common phenomenologies

Movement disorders of the mouth encompass a spectrum of hyperactive movements involving the muscles of the orofacial complex. They are rare conditions and are described in the literature primarily in case reports originating from neurologists, psychiatrists, and the dental community. The focus of this review is to provide a phenomenological description of different oral motor disorders including oromandibular dystonia, orofacial dyskinesia and orolingual tremor, and to offer management strategies for optimal treatment based on the current literature. A literature search of full text studies using PubMed/Medline and Cochrane library combined with a manual search of the reference lists was conducted until June 2021. Results from this search included meta-analyses, systematic reviews, reviews, clinical studies, case series, and case reports published by neurologists, psychiatrists, dentists and oral and maxillofacial surgeons. Data garnered from these sources were used to provide an overview of most commonly encountered movement disorders of the mouth, aiding physicians in recognizing these rare conditions and in initiating appropriate therapy.

Update on the Management of Parkinson's Disease for General Neurologists

Management of Parkinson's disease (PD) is complicated due to its progressive nature, the individual patient heterogeneity, and the wide range of signs, symptoms, and daily activities that are increasingly affected over its course. The last 10–15 years have seen great progress in the identification, evaluation, and management of PD, particularly in the advanced stages. Highly specialized information can be found in the scientific literature, but updates do not always reach general neurologists in a practical and useful way, potentially creating gaps in knowledge of PD between them and neurologists subspecialized in movement disorders, resulting in several unmet patient needs. However, general neurologists remain instrumental in diagnosis and routine management of PD. This review provides updated practical information to identify problems and resolve common issues, particularly when the advanced stage is suspected. Some tips are provided for efficient communication with the members of a healthcare team specialized in movement disorders, in order to find support at any stage of the disease in a given patient, and especially for a well-timed decision on referral.

New insights into tardive dyskinesia genetics: Implementation of whole-exome sequencing approach

Tardive dyskinesia (TD) is an adverse movement disorder induced by chronic treatment with antipsychotics drugs. The contribution of common genetic variants to TD susceptibility has been investigated in recent years, but with limited success. The aim of the current study was to investigate the potential contribution of rare variants to TD vulnerability. In order to identify TD risk genes, we performed whole-exome sequencing (WES) and gene-based collapsing analysis focusing on rare (allele frequency < 1%) and putatively deleterious variants (qualifying variants). 82 Jewish schizophrenia patients chronically treated with antipsychotics were included and classified as having severe TD or lack of any abnormal movements based on a rigorous definition of the TD phenotype. First, we performed a case-control, exome-wide collapsing analysis comparing 39 schizophrenia patients with severe TD to 3118 unrelated population controls. Then, we checked the potential top candidate genes among 43 patients without any TD manifestations. All the genes that were found to harbor one or more qualifying variants in patients without any TD features were excluded from the final list of candidate genes. Only one gene, regulating synaptic membrane exocytosis 2 (RIMS2), showed significant enrichment of qualifying variants in TD patients compared with unrelated population controls after correcting for multiple testing (Fisher's exact test p = 5.32E-08, logistic regression p = 2.50E-08). Enrichment was caused by a single variant (rs567070433) due to a frameshift in an alternative transcript of RIMS2. None of the TD negative patients had qualifying variants in this gene. In a validation cohort of 140 schizophrenia patients assessed for TD, the variant was also not detected in any individual. Some potentially suggestive TD genes were detected in the TD cohort and warrant follow-up in future studies. No significant enrichment in previously reported TD candidate genes was identified. To the best of our knowledge, this is the first WES study of TD, demonstrating the potential role of rare loss-of-function variant enrichment in this pharmacogenetic phenotype.

Distribution of non-motor symptoms in idiopathic Parkinson's disease and secondary Parkinsonism

Background

Non-motor symptoms (NMS) are frequent in patients with idiopathic Parkinson’s disease (IPD). Clinical expressions, postulated pathophysiological mechanisms, and responsiveness to antiparkinson medication represent differences between IPD and secondary Parkinsonism (SP).

Objective

To evaluate NMS expressions in IPD, SP, and a matched control group.

Methods

The accepted criteria for IPD and SP were controlled for the participants who were consecutively recruited at two outdoor patient clinics. The Well-Being Map™ was used as the evaluation instrument. These were completed by the participants before their visit. The controls consisted of non-Parkinsonian individuals who were matched by age and gender.

Results

A total of 185 participants participated in the study, IPD/SP/controls; n=73/53 and 59, respectively. The mean age was 74 years, and the median duration of disease was 6/3 years. Differences were shown between the combined IPD/SP groups and the controls. Limited differences between the IPD and SP groups could be demonstrated. Symptoms such as pain, decreased taste, as well as sleep and bladder disturbances were more frequent in the IPD group. When more than minor problems with moving were reported, disturbances in sleep and digestion were also noted to a large extent.

Conclusion

Despite differences in the pathophysiological mechanisms between IPD and SP, the study showed only minor differences in the expression of NMS. IPD and SP reported statistically more significant problems in all items compared to the controls. Sleeping problems were strongly associated with symptoms from the gastrointestinal tract, but sleep was only affected by longer disease duration to a minor extent. Motor symptoms, such as morning stiffness, were common in all three groups. Neurodegenerative diseases might have more complex expressions in common than what we have known before and it is certainly not a part of normal aging.

Anti-tuberculosis medication-induced oculogyric crisis and the importance of proper history taking

Oculogyric crisis (OGC), frequently caused by medications such as antiemetics, antidepressants, and anti-epileptics, is an acute dystonic reaction of the ocular muscles. It consists of wide-staring gaze (lasting variably from seconds to minutes), seizures, and a widely-opened mouth. To date, there have been no reports of anti-tuberculosis medications such as rifampicin, isoniazid, pyrazinamide or ethambutol inducing OGC. It is of utmost importance to recognize this adverse reaction, which could be incorrectly diagnosed as an anaphylactic-like reaction. In this paper, we highlight a case of a 66-year-old Indian man who presented with OGC induced by anti-tuberculosis medications which was initially suspected to be an anaphylactic reaction and was subsequently halted with the administration of diphenhydramine.

Clinical Experience With Perampanel for Refractory Pediatric Epilepsy in One Canadian Center

Perampanel (PER) is a new antiseizure medication that inhibits the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) class of glutamate receptors. It is important for physicians to be aware of the efficacy and tolerability of new drugs in the postmarketing phase. We performed a retrospective review of our experience with perampanel at BC Children's Hospital. Twenty-four pediatric patients prescribed perampanel from 2014 to 2016 were identified. Fifteen (63%) discontinued perampanel, and 10 (42%) had greater than 50% reduction in seizures. Twelve (50%) had behavioral and 8 (33%) had nonbehavioral adverse events. One-third experienced serious adverse events. One patient experienced oculogyric crisis, which is not previously reported with perampanel. Adverse events were not dose related and were reversible. Possible risk factors for behavioral adverse events include a history of behavioral problems with other antiseizure medications and preexisting behavioral comorbidities. It is important to counsel patients about the potential for serious adverse events, particularly behavioral, when prescribing perampanel.

Selective Serotonin Reuptake Inhibitor/Serotonin-Norepinephrine Reuptake Inhibitor Use as a Predictor of a Diagnosis of Restless Legs Syndrome

OBJECTIVE/BACKGROUND

Because restless legs syndrome (RLS) is a problematic syndrome, demonstrating an association between use of selective serotonin reuptake inhibitors (SSRIs)/serotonin-norepinephrine reuptake inhibitors (SNRIs) and RLS may help direct patient care. The goals of this study were (1) to establish the incidence of RLS in mental health patients being treated with SSRIs or SNRIs in a local Veterans Affairs medical center and (2) to evaluate the frequency with which certain SSRIs or SNRIs are associated with RLS and the trend in frequency of the diagnosis since the revision of the criteria for RLS offered by the International Restless Leg Syndrome Study Group (IRLSSG), the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and the International Classification of Sleep Disorders, Revised (ICSD-3).

METHODS

A retrospective chart review was used to evaluate the number of patients receiving SSRI/SNRI therapy with and without a diagnosis of RLS, with the date of the RLS diagnosis and initiation of SSRI/SNRI therapy noted. The frequency with which certain SSRIs/SNRIs were associated with RLS, and the frequency of RLS diagnoses since January 2012 were also noted. Descriptive statistics and logistic regression were used for data analysis.

RESULTS

A total of 254 charts were reviewed. A majority of the patients (89.8%) were male, and 14 (5.5%) were diagnosed with RLS. A logistic regression equation approached significance in predicting RLS (P=0.053). Age and sex emerged as significant predictors of RLS. The prevalence of any individual SSRI or SNRI being associated with RLS was indeterminable. No difference was seen in the number of RLS diagnoses since the refining of the IRLSSG, DSM-5, and ICSD-3 criteria.

CONCLUSIONS

The use of SSRIs/SNRIs does not seem to be associated with a diagnosis of RLS. In addition, the diagnosis of RLS does not seem to have become more common since the revision of the diagnostic criteria for the disorder.

Phencyclidine Induced Oculogyric Crisis Responding Well to Conventional Treatment

Background. Oculogyric crisis is a form of acute dystonic reaction characterized by involuntary upward deviation of eye ball. Its causes are broad with antipsychotics and antiemetics as the most common causes. Case Presentation. A 25-year-old man with the past medical history of marijuana use presented to ED with involuntary upward deviation of eye 1 day after using phencyclidine (PCP) for the first time. He did not have any other symptoms and was hemodynamically stable. All laboratory investigations were normal except urine drug screen which was positive for PCP. Patient was treated with IV diphenhydramine which improved his symptoms. Conclusion. Illicit drug abuse is a growing problem in our society with increasingly more patients presenting to ED with its complications. The differential diagnosis of acute dystonic reactions should be extended to include illicit drugs as the potential cause of reversible acute dystonias especially in high risk patients.

Altered theta oscillations and aberrant cortical excitatory activity in the 5XFAD model of Alzheimer's disease

Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by impairment of memory function. The 5XFAD mouse model was analyzed and compared with wild-type (WT) controls for aberrant cortical excitability and hippocampal theta oscillations by using simultaneous video-electroencephalogram (EEG) monitoring. Seizure staging revealed that 5XFAD mice exhibited cortical hyperexcitability whereas controls did not. In addition, 5XFAD mice displayed a significant increase in hippocampal theta activity from the light to dark phase during nonmotor activity. We also observed a reduction in mean theta frequency in 5XFAD mice compared to controls that was again most prominent during nonmotor activity. Transcriptome analysis of hippocampal probes and subsequent qPCR validation revealed an upregulation of Plcd4 that might be indicative of enhanced muscarinic signalling. Our results suggest that 5XFAD mice exhibit altered cortical excitability, hippocampal dysrhythmicity, and potential changes in muscarinic signaling.

Pharmacogenetics of antipsychotic-induced movement disorders as a resource for better understanding Parkinson's disease modifier genes

Antipsychotic-induced movement disorders are major side effects of antipsychotic drugs among schizophrenia patients, and include antipsychotic-induced parkinsonism (AIP) and tardive dyskinesia (TD). Substantial pharmacogenetic work has been done in this field, and several susceptibility variants have been suggested. In this paper, the genetics of antipsychotic-induced movement disorders is considered in a broader context. We hypothesize that genetic variants that are risk factors for AIP and TD may provide insights into the pathophysiology of motor symptoms in Parkinson’s disease (PD). Since loss of dopaminergic stimulation (albeit pharmacological in AIP and degenerative in PD) is shared by the two clinical entities, genes associated with susceptibility to AIP may be modifier genes that influence clinical expression of PD motor sub-phenotypes, such as age at onset, disease severity, or rate of progression. This is due to their possible functional influence on compensatory mechanisms for striatal dopamine loss. Better compensatory potential might be beneficial at the early and later stages of the PD course. AIP vulnerability variants could also be related to latent impairment in the nigrostriatal pathway, affecting its functionality, and leading to subclinical dopaminergic deficits in the striatum. Susceptibility of PD patients to early development of l-DOPA induced dyskinesia (LID) is an additional relevant sub-phenotype. LID might share a common genetic background with TD, with which it shares clinical features. Genetic risk variants may predispose to both phenotypes, exerting a pleiotropic effect. According to this hypothesis, elucidating the genetics of antipsychotic-induced movement disorders may advance our understanding of multiple aspects of PD and it clinical course, rendering this a potentially rewarding field of study.

Canadian Association of Neurosciences Review: The Role of Dopamine Receptor Function in Neurodegenerative Diseases

Dopamine (DA) receptors, which are heavily expressed in the caudate/putamen of the brain, represent the molecular target of several drugs used in the treatment of various neurological disorders, such as Parkinson's disease. Although most of the drugs are very effective in alleviating the symptoms associated with these conditions, their long-term utilization could lead to the development of severe side-effects. In addition to uncovering novel mediators of physiological DA receptor functions, recent research advances are suggesting a role of these receptors in toxic effects on neurons. For instance, accumulating evidence indicates that DA receptors, particularly D1 receptors, are central in the neuronal toxicity induced by elevated synaptic levels of DA. In this review, we will discuss recent findings on DA receptors as regulators of long term neuronal dysfunction and neurodegenerative processes.

Upregulation of dopamine D3, not D2, receptors correlates with tardive dyskinesia in a primate model

Tardive dyskinesia (TD) is a delayed and potentially irreversible motor complication arising in patients chronically exposed to centrally active dopamine D2 receptor antagonists, including antipsychotic drugs and metoclopramide. The classical dopamine D2 receptor supersensitivity hypothesis in TD, which stemmed from rodent studies, lacks strong support in humans. To investigate the neurochemical basis of TD, we chronically exposed adult capuchin monkeys to haloperidol (median, 18.5 months; n = 11) or clozapine (median, 6 months; n = 6). Six unmedicated animals were used as controls. Five haloperidol-treated animals developed mild TD movements, and no TD was observed in the clozapine group. Using receptor autoradiography, we measured striatal dopamine D1, D2, and D3 receptor levels. We also examined the D3 receptor/preprotachykinin messenger RNA (mRNA) co-expression, and quantified preproenkephalin mRNA levels, in striatal sections. Unlike clozapine, haloperidol strongly induced dopamine D3 receptor binding sites in the anterior caudate-putamen, particularly in TD animals, and binding levels positively correlated with TD intensity. Interestingly, the D3 receptor upregulation was observed in striatonigral neurons. In contrast, D2 receptor binding was comparable to controls, and dopamine D1 receptor binding was reduced in the anterior putamen. Enkephalin mRNA widely increased in all animals, but to a greater extent in TD-free animals. These results suggest for the first time that upregulated striatal D3 receptors correlate with TD in nonhuman primates, adding new insights to the dopamine receptor supersensitivity hypothesis. The D3 receptor could provide a novel target for drug intervention in human TD.

Tardive dyskinesia in relation to estimated dopamine D2 receptor occupancy in patients with schizophrenia: analysis of the CATIE data

OBJECTIVE

The objective of this study was to evaluate the relationship between antipsychotic-induced tardive dyskinesia (TD) and estimated dopamine D2 receptor occupancy levels in patients with schizophrenia, using the dataset from the Clinical Antipsychotic Trials in Intervention Effectiveness (CATIE).

METHODS

The dataset from 218 subjects (risperidone, N=78; olanzapine, N=100; ziprasidone, N=40) who presented with a score of zero on the Abnormal Involuntary Movement Scale (AIMS) at baseline in Phase 1 of the CATIE study, and remained for ≥6months, was used. Peak and trough dopamine D2 receptor occupancy levels on the day of the AIMS assessment at the endpoint were estimated from plasma antipsychotic concentrations, using population pharmacokinetic analysis and our D2 prediction model. The estimated dopamine D2 receptor occupancy levels were compared between patients who presented an AIMS score of ≥2 at endpoint and those with a score of zero, using the Mann-Whitney U test.

RESULTS

Estimated dopamine D2 receptor occupancy levels at trough were significantly higher in subjects who developed involuntary movements (N=23) than those who did not (N=195) (71.7±14.4% vs. 64.3±19.3%, p<0.05) while no significant difference was found in the estimated peak D2 receptor occupancy between them (75.4±8.7% vs. 72.1±9.9%, p=0.07). When the analyses were separately conducted for the three drugs, there were no significant differences in estimated peak or trough D2 occupancy although the values were consistently numerically higher among those developing involuntary movements.

CONCLUSION

Greater dopamine D2 receptor blockade with antipsychotics at trough might increase the risk of tardive involuntary movements although this finding needs to be replicated in larger trials.

Beneficial effect of candesartan and lisinopril against haloperidol-induced tardive dyskinesia in rat

INTRODUCTION

Tardive dyskinesia is a serious motor disorder of the orofacial region, resulting from chronic neuroleptic treatment of schizophrenia. Candesartan (AT1 antagonist) and lisinopril (ACE inhibitor) has been reported to possess antioxidant and neuroprotective effects. The present study is designed to investigate the effect of candesartan and lisinopril on haloperidol-induced orofacial dyskinesia and oxidative damage in rats.

MATERIALS AND METHODS

Tardive dyskinesia was induced by administering haloperidol (1 mg/kg i.p.) and concomitantly treated with candesartan (3 and 5 mg/kg p.o.) and lisinopril (10 and 15 mg/kg p.o.) for 3 weeks in male Wistar rats. Various behavioral parameters were assessed on days 0, 7, 14 and 21 and biochemical parameters were estimated at day 22.

RESULTS

Chronic administration of haloperidol significantly increased stereotypic behaviors in rats, which were significantly improved by administration of candesartan and lisinopril. Chronic administration of haloperidol significantly increased oxidative stress and neuro-inflammation in the striatum region of the rat's brain. Co-administration of candesartan and lisinopril significantly attenuated the oxidative damage and neuro-inflammation in the haloperidol-treated rat.

CONCLUSIONS

The present study supports the therapeutic use of candesartan and lisinopril in the treatment of typical antipsychotic-induced orofacial dyskinesia and possible antioxidant and neuro-inflammatory mechanisms.

Acute dystonic reaction as medical emergency: a report of two cases

Drug-induced dystonic reactions are common presentations to the emergency department. Two cases of acute dystonic reactions presenting as acute medical emergency illustrate the associated fatality and possibility of misdiagnosis. This case series reports two cases of medication-induced (haloperidol and metoclopramide) acute dystonic reactions presenting with torticollis, tongue protrusion, and respiratory distress which resolved with the administration of intramuscular biperiden and oxygen by facemask. In developing countries like Nigeria where atypical anti-psychotic medications with fewer and lesser troublesome side effects are not affordable to many, the training of physicians and other doctors should adequately include a high degree of clinical suspicion and knowledge of management of acute dystonic reactions.

Do tardive dyskinesia and L-dopa induced dyskinesia share common genetic risk factors? An exploratory study

Tardive dyskinesia (TD) in schizophrenia patients treated with antipsychotic medications and L-dopa induced dyskinesia (LID) among Parkinson's disease (PD) affected individuals share similar clinical features. Both conditions are induced by chronic exposure to drugs that target dopaminergic receptors (antagonists in TD and agonists in LID) and cause pulsatile and nonphysiological stimulation of these receptors. We hypothesized that the two motor adverse effects partially share genetic risk factors such that certain genetic variants exert a pleiotropic effect, influencing susceptibility to TD as well as to LID. In this pilot study, we focused on 21 TD-associated SNPs, previously reported in TD genome-wide association studies or in candidate gene studies. By applying logistic regression and controlling for relevant clinical risk factors, we studied the association of the SNPs with LID vulnerability in two independent pharmacogenetic samples. We included a Jewish Israeli sample of 203 PD patients treated with L-dopa for a minimum of 3 years and evaluated the existence or absence of LID (LID+ = 128; LID- = 75). An Italian sample was composed of early LID developers (within the first 3 years of treatment, N = 187) contrasted with non-early LID developers (after 7 years or more of treatment, N = 203). None of the studied SNPs were significantly associated with LID susceptibility in the two samples. Therefore, we were unable to obtain proof of concept for our initial hypothesis of an overlapping contribution of genetic risk factors to TD and LID. Further studies in larger samples are required to reach definitive conclusions.

Tics and other stereotyped movements as side effects of pharmacological treatment

Tics and other stereotyped abnormal movements can be seen as adverse effects of some pharmacologic drugs. Among these drugs, antipsychotics may provoke tardive syndromes after a chronic exposure, primarily in the case of typical antipsychotics. These syndromes include tardive tics, tardive dyskinesia, or tardive akathisia, which present with tics or stereotyped movements as a clinical phenomenon. Psychostimulants (mainly methylphenidate) have traditionally been associated with the appearance of tics due to the increased dopamine activity caused by stimulants. Nevertheless, in recent years, several studies have concluded not only that methylphenidate does not exacerbate or reactivate tics but also that tics can improve with its use in patients with associated attention deficit and hyperactivity disorder and tic disorder. Antiepileptic drugs, although infrequently, can also induce tics, with carbamazepine and lamotrigine described as tic inducers. Other antiepileptics, including levetiracetam and topiramate, have been proposed as a potential treatment for tic disorders due to a positive effect on tics, especially in those with associated epileptic disorder. Clinical and therapeutic approaches to tics and stereotyped movements after exposure to antipsychotics, stimulants, and antiepileptic drugs will be reviewed in this chapter.

Contribution of orodental status to the intensity of orofacial tardive dyskinesia: an interdisciplinary and video-based assessment

BACKGROUND

Tardive dyskinesia (TD) is a neurological motor complication eventually arising in one-third of patients chronically exposed to antipsychotic drugs. Some orodental peripheral factors have been reported to influence TD.

OBJECTIVE

To measure orodental factors such as temporomandibular joint function, static occlusal contacts, and denture condition, and attempt correlations with orofacial TD intensity.

METHODS

In this exploratory cross-sectional pilot study, 31 subjects between 30 and 75 years of age were divided in two groups displaying minimal to mild, or moderate to severe orofacial TD, respectively, and underwent a detailed oral, dental, and prosthetic evaluation to capture various aspects of oral health compared between the two groups. Blinded video-based TD ratings along a validated scale were obtained to compare dentulous and edentulous subjects, and contrast TD intensity in complete denture wearers with and without their own prostheses.

RESULTS

None of the factors examined tightly correlated with orofacial TD intensity. However, edentulism was associated with a higher median orofacial TD rating compared to the dentulous group (p = 0.001). Further, a significant intra-subject difference was observed in the edentulous subjects rated with their own complete dentures in place or not (p = 0.028), the dentures attenuating the mean orofacial ratings by 21.8 ± 7.3%.

CONCLUSION

Of all orodental factors considered, only edentulism and complete denture wearing influenced oral TD expression, calling for the close monitoring of the dental status in antipsychotic drug-exposed patients to prevent tooth loss. Further studies to measure the impact of an adequate prosthodontic rehabilitation in edentulous subjects with orofacial TD seem warranted.

Relevance of animal models to human tardive dyskinesia

Tardive dyskinesia remains an elusive and significant clinical entity that can possibly be understood via experimentation with animal models. We conducted a literature review on tardive dyskinesia modeling. Subchronic antipsychotic drug exposure is a standard approach to model tardive dyskinesia in rodents. Vacuous chewing movements constitute the most common pattern of expression of purposeless oral movements and represent an impermanent response, with individual and strain susceptibility differences. Transgenic mice are also used to address the contribution of adaptive and maladaptive signals induced during antipsychotic drug exposure. An emphasis on non-human primate modeling is proposed, and past experimental observations reviewed in various monkey species. Rodent and primate models are complementary, but the non-human primate model appears more convincingly similar to the human condition and better suited to address therapeutic issues against tardive dyskinesia.

Support for association of HSPG2 with tardive dyskinesia in Caucasian populations

Tardive dyskinesia (TD) is a severe adverse effect of chronic antipsychotic drug treatment. In addition to clinical risk factors, TD susceptibility is influenced by genetic predisposition. Recently, Syu et al. (2010) reported a genome-wide association screening of TD in Japanese schizophrenia patients. The best result was association of single-nucleotide polymorphism (SNP) rs2445142 in the HSPG2 (heparan sulfate proteoglycan 2) gene with TD. In the present study, we report a replication study of the five top Japanese TD-associated SNPs in two Caucasian TD samples. Applying logistic regression and controlling for relevant clinical risk factors, we were able to replicate the association of HSPG2 SNP rs2445142 with TD in a prospective study sample of 179 Americans of European origin by performing a secondary analysis of the CATIE (Clinical Antipsychotic Trials of Intervention Effectiveness) genome-wide association study data set, and using a perfect proxy surrogate marker (rs878949; P = 0.039). An association of the 'G' risk allele of HSPG2 SNP rs2445142 with TD was also shown in a sample of Jewish Israeli schizophrenia patients (retrospective, cross-sectional design; P = 0.03). Although the associations were only nominally significant, the findings provide further support for the possible involvement of HSPG2 in susceptibility to TD.

Genome-wide association study of antipsychotic-induced parkinsonism severity among schizophrenia patients

RATIONALE

Antipsychotic-induced parkinsonism (AIP) is a severe adverse affect of neuroleptic treatment. Interindividual heterogeneity in AIP development and severity is associated with risk factors such as antipsychotic drug type, old age, and female gender. There is evidence for genetic predisposition to develop AIP but the variants that confer susceptibility or protection are mostly unknown.

OBJECTIVE

To identify genes related to AIP susceptibility, we performed a pharmacogenomic genome-wide association study (GWAS) for AIP severity.

METHODS

Three hundred ninety-seven American schizophrenia patients who participated in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE)-GWAS project were included in our analysis. Patients had been randomized to treatment with antipsychotic monotherapy for periods ranging from 2 weeks to 18 months during phase 1 of the CATIE trial. They were regularly assessed for AIP severity using the modified Simpson-Angus Scale (SAS). For statistical analysis, patients were dichotomized as cases (average SAS mean global score > 0.3 during CATIE phase 1, N = 199) or controls (average SAS mean global score 0, N = 198).

RESULTS

Using logistic regression and controlling for population stratification, age, gender, SAS score at baseline, and concomitant use of anticholinergic drugs, we identified several single-nucleotide polymorphisms associated with AIP severity. Although none reached the GWAS significance level of P < 4.2 x 10(-7), some promising candidate genes for further research on genetic predisposition to AIP were identified including EPF1, NOVA1, and FIGN.

CONCLUSIONS

Our finding may contribute to understanding of the pathophysiology of AIP as well as to a priori identification of patients vulnerable for development of AIP.

Drug-Induced Movement Disorders in Older Adults: An Overview for Clinical Practitioners

OBJECTIVE

To provide an overview of some of the most common drug-induced movement disorders (DIMD) seen in the elderly by the primary care clinician. The epidemiology, clinical presentation, differential diagnosis, treatment, risk factors, and preventive measures are presented for each DIMD.

DATA SOURCES

Medical literature and research article search utilizing PubMed (National Library of Medicine), Psych INFO (American Psychological Association), CINAHL Database (CINAHL Information Systems), the Library of Congress Catalogue, and the Internet.

STUDY SELECTION

Reviews and articles from 1954 to 2005 concerning various movement disorders associated with medication in older adults. DATA EXTRACTIONS: Data on movement disorders associated with medications ranging from possible or controversial to well-established.

DATA SYNTHESIS

With the aging of populations in the United States and other countries, the use of medications with potential risk of precipitating movement disorders is increasing. The majority of these iatrogenic problems will be first seen in the geriatric patient in various clinical settings, typically in a primary care setting. To a large extent they will be observed in patients with mild cognitive impairment or dementia having impaired recall and reduced capacity to participate in the diagnostic interview. The challenge to clinicians is complicated by the sizable number of medications that may be involved.

Trends in the molecular pathogenesis and clinical therapeutics of common neurodegenerative disorders

The term neurodegenerative disorders, encompasses a variety of underlying conditions, sporadic and/or familial and are characterized by the persistent loss of neuronal subtypes. These disorders can disrupt molecular pathways, synapses, neuronal subpopulations and local circuits in specific brain regions, as well as higher-order neural networks. Abnormal network activities may result in a vicious cycle, further impairing the integrity and functions of neurons and synapses, for example, through aberrant excitation or inhibition. The most common neurodegenerative disorders are Alzheimer’s disease, Parkinson’s disease, Amyotrophic Lateral Sclerosis and Huntington’s disease. The molecular features of these disorders have been extensively researched and various unique neurotherapeutic interventions have been developed. However, there is an enormous coercion to integrate the existing knowledge in order to intensify the reliability with which neurodegenerative disorders can be diagnosed and treated. The objective of this review article is therefore to assimilate these disorders’ in terms of their neuropathology, neurogenetics, etiology, trends in pharmacological treatment, clinical management, and the use of innovative neurotherapeutic interventions.

Association of the RGS2 gene with extrapyramidal symptoms induced by treatment with antipsychotic medication

OBJECTIVES

To investigate the role of genes encoding regulators of G protein signaling in early therapeutic response to antipsychotic drugs and in susceptibility to drug-induced extrapyramidal symptoms. As regulators of G protein signaling and regulators of G protein signaling-like proteins play a pivotal role in dopamine receptor signaling, genetically based, functional variation could contribute to interindividual variability in therapeutic and adverse effects.

METHODS

Consecutively hospitalized, psychotic patients with Diagnostic and Statistical Manual of Mental Disorder-IV schizophrenia (n=121) were included in the study if they received treatment with typical antipsychotic medication (n=72) or typical antipsychotic drugs and risperidone (n=49) for at least 2 weeks. Clinical state and adverse effects were rated at baseline and after 2 weeks. Twenty-four single nucleotide polymorphisms were genotyped in five regulators of G protein signaling genes.

RESULTS

None of the single nucleotide polymorphisms were related to clinical response to antipsychotic treatment at 2 weeks. Five out of six single nucleotide polymorphisms within or flanking the RGS2 gene were nominally associated with development or worsening of parkinsonian symptoms (PARK+) as measured by the Simpson Angus Scale, one of them after correction for multiple testing (rs4606, P=0.002). A GCCTG haplotype encompassing tagging single nucleotide polymorphisms within and flanking RGS2 was significantly overrepresented among PARK+ compared with PARK--patients (0.23 vs. 0.08, P=0.003). A second, 'protective', GTGCA haplotype was significantly overrepresented in PARK--patients (0.13 vs. 0.30, P=0.009). Both haplotype associations survive correction for multiple testing.

CONCLUSIONS

Subject to replication, these findings suggest that genetic variation in the RGS2 gene is associated with susceptibility to extrapyramidal symptoms induced by antipsychotic drugs.

A network dysfunction perspective on neurodegenerative diseases

Patients with Alzheimer's disease or other neurodegenerative disorders show remarkable fluctuations in neurological functions, even during the same day. These fluctuations cannot be caused by sudden loss or gain of nerve cells. Instead, it is likely that they reflect variations in the activity of neural networks and, perhaps, chronic intoxication by abnormal proteins that the brain is temporarily able to overcome. These ideas have far-reaching therapeutic implications.

Serum creatine kinase levels in chronic psychosis patients--a comparison between atypical and conventional antipsychotics

Creatine kinase is an important enzyme in the energy metabolism of many cell types, including muscle cells. Increased serum levels of creatine kinase may serve as a marker of enhanced creatine kinase synthesis in muscle cells or muscle cell membrane damage. The purpose of this study was to compare serum creatine kinase levels in chronic psychosis patients treated with either atypical or conventional antipsychotics. Forty-nine patients, receiving clozapine (n=18), or olanzapine (n=18), or conventional agents (n=13), were studied. Fasting serum samples were analyzed for creatine kinase. A significant difference in median creatine kinase level was found among the treatment groups (p=0.03), in that the creatine kinase level was higher both in the patients receiving clozapine and in the patients receiving olanzapine, compared to that in patients receiving conventional antipsychotics, p=0.001 and p<0.0001, respectively. In addition, elevated creatine kinase levels above the upper limit of normal were found in 6 (17%) of the patients treated with clozapine or olanzapine, but in none of the patients treated with conventional agents. In summary, the present results indicate that therapy with atypical antipsychotics like clozapine and olanzapine, in contrast to conventional agents, may be associated with serum creatine kinase elevation.

Successful electroconvulsive treatment of depression associated with a marked reduction in the symptoms of tardive dyskinesia

This report describes improvement of tardive dyskinesia (TD) in a patient who received electroconvulsive therapy (ECT) for depression. The patient, an elderly Asian male, was treated for major depression with ECT and showed a rapid improvement of TD that may have been caused by any number of drugs or combination of drugs. We discuss the possibility of improving TD by treating the depression with ECT.

Adrafinil-induced orofacial dyskinesia

We describe the first case of orofacial abnormal movements induced by adrafinil, a vigilance promoting agent of the same pharmacological class as modafinil. The dyskinesias did not spontaneously recover despite adrafinil withdrawal for a 4-month period. They were secondly dramatically improved by tetrabenazine, a presynaptic dopaminergic depleting drug which was introduced after the 4-month adrafinil-free period.

Tremblements et mouvements anormaux aigus d’origine médicamenteuse

The main clinical characteristics and aetiology of drug-induced tremor and acute movement disorders (myoclonus, chorea, athetosis, dyskinesia, dystonia, tics) are reviewed and discussed in this article. Tremor is the most frequent drug-induced acute movement disorder. Drug intake (and, initially, true or 'hidden' neuroleptic or psychoactive drugs) should be suspected as the cause of every abnormal movement. Drug-induced acute movement disorders usually disappear spontaneously after withdrawal of the suspected drug without any drug treatment. Drug-induced tremor and movement disorders are often poorly described in the Summary of Products Characteristics (SPC).