Effect of cholinergic and anticholinergic agents on tardive dyskinesia

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.

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

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

Attenuated facial movement in depressed women is associated with symptom severity, and nucleus accumbens functional connectivity

It is assumed that mood can be inferred from one's facial expression. While this association may prove to be an objective marker for mood disorders, few studies have explicitly evaluated this linkage. The facial movement responses of women with major depressive disorder (n = 66) and healthy controls (n = 46) under emotional stimuli were recorded using webcam. To boost facial movements, the naturalistic audio-visual stimuli were presented. To assess consistent global patterns across facial movements, scores for facial action units were extracted and projected onto principal component using principal component analysis. The associations of component for facial movements with functional brain circuitry was also investigated. Clusters of mouth movements, such as lip press and stretch, identified by principal component analysis, were attenuated in depressive patients compared to those in healthy controls. This component of facial movements was associated with depressive symptoms, and the strengths of resting brain functional connectivity between nucleus accumbens and both posterior insular cortex and thalamus. The evaluation of facial movements may prove to be a promising quantitative marker for assessing depressive symptoms and their underlying brain circuitry.

Tardive dyskinesia

Tardive dyskinesia is a group of hyperkinetic and hypokinetic movement disorders, following the administration of dopamine receptor-blocking drugs. The severity of these syndromes varies from soft forms to the development of life-degrading situations. Phenomenologically tardive dyskinesia can be represented both in isolation and in various combinations. Recognition of these syndromes early in the development of tardive dyskinesia can optimize therapeutic treatment and reduce the risk of severe complications. As a means of treatment, deutetrabenazine or valbenazine are used as first-line drugs, with resistance to therapy and in severe cases, drugs of other groups are used (amantadine, baclofen, botulinum toxin type A, clonazepam, donepezil, gabapentin, ginkgo biloba, levetiracetam, melatonin, pregabalin, thiamine, verapamil, vitamin B6, vitamin E). Our own experience of 12 patients with tardive dystonia showed the effeciency of local injections of botulinum toxin.

Cumulative Burden of Illness in Veterans With Tardive Dyskinesia and Serious Mental Disorders

PURPOSE/BACKGROUND

To inform cost-benefit decisions for veterans, the risk of tardive dyskinesia (TD) and its impact on comorbidities and outcomes were assessed.

METHODS/PROCEDURES

In a retrospective study, veterans with schizophrenia/schizoaffective, and bipolar and major depressive disorders receiving antipsychotics during the period October 1, 2014, to September 30, 2015, were identified. Tardive dyskinesia was determined by International Classification of Diseases, Ninth Revision, Clinical Modification codes. Correlates of TD were examined using χ or t tests. Odds ratios (ORs) and β parameters with 95% confidence intervals (CIs) for categorical and continuous variables associated with TD were derived from a multivariate logistic and linear regression, respectively.

FINDINGS/RESULTS

Among 7985 veterans, 332 (4.2%) were diagnosed as having possible TD. The odds of having TD were higher for older veterans (OR, 1.04; 95% CI, 1.03-1.05; P < 0.0001) and veterans with schizophrenia/schizoaffective disorder (OR, 1.54; 95% CI, 1.23-1.91; P < 0.0001) or diabetes (OR, 1.64; 95% CI, 1.30-2.06; P < 0.0001). Veterans with TD received more antipsychotic prescriptions (mean ± SD, 18.4 ± 30.3 vs 13.3 ± 26.4; P = 0.003) and days of supply (233.9 ± 95.4 vs 211.4 ± 102.0; P < 0.0001). They were more likely to have received 2 or more antipsychotics (27.1% vs 19.7%, P = 0.0009) and benztropine (OR, 2.25: 95% CI 1.73-2.91; P < 0.0001). Veterans with TD had a higher Charlson Comorbidity Index score (β = 0.32; SE, 0.09; 95% CI, 0.14-0.49; P = 0.0003) and higher odds of any medical hospitalization (OR, 1.45; 95% CI, 1.07-1.95; P = 0.001).

IMPLICATIONS/CONCLUSIONS

The diagnosis of possible TD was associated with older age, schizophrenia/schizoaffective disorder, medical comorbidity, and hospitalization. Tardive dyskinesia may be a marker for patients at risk of adverse health care outcomes and diminished quality of life.

[Antipsychotic-induced motor symptoms in schizophrenic psychoses-Part 3 : Tardive dyskinesia]

The treatment of schizophrenic psychoses with antipsychotic drugs (AP) is often associated with an increased risk of delayed occurrence of antipsychotic-associated movement disorders. Persistence and chronicity of such symptoms are very frequent. The risk of developing tardive dyskinesia (TD) is associated with the pharmacological effect profile of a particular AP, with treatment duration and age. This systematic review article summarizes the current study situation on prevalence, risk factors, prevention and treatment options and instruments for early prediction of TD in schizophrenic psychoses. The current data situation on treatment strategies for TD is very heterogeneous. For the treatment of TD there is preliminary evidence for reduction or discontinuation of the AP, switching to clozapine, administration of benzodiazepines (clonazepam) and treatment with vesicular monoamine transporter (VMAT2) inhibitors, ginkgo biloba, amantadine or vitamin E. Although TD can be precisely diagnosed it cannot always be effectively treated. Early detection and early treatment of TD can have a favorable influence on the prognosis and the clinical outcome.

Cholinergic medication for antipsychotic-induced tardive dyskinesia

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

An electronic search of the Cochrane Schizophrenia Group's Study-Based Register of Trials (16 July 2015 and April 2017) was undertaken. This register is assembled by extensive searches for randomised controlled trials in many electronic databases, registers of trials, conference proceedings and dissertations. References of all identified studies were searched for further trial citations.

SELECTION CRITERIA

We included reports identified by the search if they were of controlled trials involving people with antipsychotic-induced TD and chronic mental illness, who had been randomly allocated to either a cholinergic agent or to a placebo or no intervention. Two review authors independently assessed the methodological quality of the trials.

DATA COLLECTION AND ANALYSIS

Two review authors extracted data and, where possible, estimated risk ratios (RR) or mean differences (MD), with 95% confidence intervals (CI). We analysed data on an intention-to-treat basis, with the assumption that people who left early had no improvement. We assessed risk of bias and created a 'Summary of findings' table using GRADE.

MAIN RESULTS

We included 14 studies investigating the use of cholinergic drugs compared with placebo published between 1976 and 2014. All studies involved small numbers of participants (five to 60 people). Three studies that investigated the new cholinergic Alzheimer drugs for the treatment of TD are new to this update. Overall, the risk of bias in the included studies was unclear, mainly due to poor reporting; allocation concealment was not described, generation of the sequence was not explicit, studies were not clearly blinded, we are unsure if data are incomplete, and data were often poorly or selectively reported.We are uncertain about the effect of new or old cholinergic drugs on no clinically important improvement in TD symptoms when compared with placebo; the quality of evidence was very low (RR 0.89, 95% CI 0.65 to 1.23; 27 people, 4 RCTs). Eight trials found that cholinergic drugs may make little or no difference to deterioration of TD symptoms (low-quality evidence, RR 1.11, 95% CI 0.55 to 2.24; 147 people). Again, due to very low-quality evidence, we are uncertain about the effects on mental state (RR 0.50, 95% CI 0.10 to 2.61; 77 people, 5 RCTs), adverse events (RR 0.56, 95% CI 0.15 to 2.14; 106 people, 4 RCTs), and leaving the study early (RR 1.09,95% CI 0.56 to 2.10; 288 people 12 RCTs). No study reported on social confidence, social inclusion, social networks, or personalised quality of life.

AUTHORS' CONCLUSIONS

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

Historical perspectives on tardive dyskinesia

Tardive dyskinesia (TD) is a persistent hyperkinetic movement disorder associated with dopamine receptor blocking agents including antipsychotic medications. Although uncertainty and concern about this drug side effect have vacillated since its initial recognition 60 years ago, recent commercial interest in developing effective treatments has rekindled scientific and clinical interest after a protracted period of neglect. Although substantial research has advanced knowledge of the clinical features and epidemiology of TD, many fundamental questions raised by early investigators remain unresolved. In this paper, we review the early clinical reports that led to the acceptance of TD as an iatrogenic disorder and the lingering controversies that emerged thereafter. Continued research on TD as a serious adverse reaction to treatment may not only enhance patient outcomes and recovery efforts but may also provide insights into both the mechanism of action of antipsychotic drugs and the nosology and pathophysiology of idiopathic psychomotor disorders.

Medications influencing central cholinergic pathways affect fixation stability, saccadic response time and associated eye movement dynamics during a temporally-cued visual reaction time task

RATIONALE

Anticholinergic medications largely exert their effects due to actions on the muscarinic receptor, which mediates the functions of acetylcholine in the peripheral and central nervous systems. In the central nervous system, acetylcholine plays an important role in the modulation of movement.

OBJECTIVE

This study investigated the effects of over-the-counter medications with varying degrees of central anticholinergic properties on fixation stability, saccadic response time and the dynamics associated with this eye movement during a temporally-cued visual reaction time task, in order to establish the significance of central cholinergic pathways in influencing eye movements during reaction time tasks.

METHODS

Twenty-two participants were recruited into the placebo-controlled, human double-blind, four-way crossover investigation. Eye tracking technology recorded eye movements while participants reacted to visual stimuli following temporally informative and uninformative cues. The task was performed pre-ingestion as well as 0.5 and 2 h post-ingestion of promethazine hydrochloride (strong centrally acting anticholinergic), hyoscine hydrobromide (moderate centrally acting anticholinergic), hyoscine butylbromide (anticholinergic devoid of central properties) and a placebo.

RESULTS

Promethazine decreased fixation stability during the reaction time task. In addition, promethazine was the only drug to increase saccadic response time during temporally informative and uninformative cued trials, whereby effects on response time were more pronounced following temporally informative cues. Promethazine also decreased saccadic amplitude and increased saccadic duration during the temporally-cued reaction time task.

CONCLUSION

Collectively, the results of the study highlight the significant role that central cholinergic pathways play in the control of eye movements during tasks that involve stimulus identification and motor responses following temporal cues.

Medications influencing central cholinergic neurotransmission affect saccadic and smooth pursuit eye movements in healthy young adults

RATIONALE

Acetylcholine is an important neuromodulator in the central nervous system, where it plays a significant role in central functions such as the regulation of movement.

OBJECTIVE

This study investigated the pharmacological effects of over-the-counter anticholinergic medications on saccadic and smooth pursuit eye movements, in order to establish the significance of central cholinergic pathways in the control of these centrally regulated oculomotor processes.

METHODS

Sixteen subjects (mean age 23 ± 3 years, 9 females) performed pro-saccadic, anti-saccadic and smooth pursuit eye movement tests, while an eye tracker collected eye movement data. Oculomotor assessments were performed pre-ingestion, 0.5 and 2 h post-ingestion of drugs with varying degrees of central anticholinergic properties. The drugs tested were promethazine, hyoscine hydrobromide, hyoscine butylbromide and placebo.

RESULTS

The drug intervention with stronger central anticholinergic properties, promethazine, decreased amplitude and increased velocity in the pro-saccadic task and increased duration in the anti-saccadic task. Promethazine, once again, was the only drug to decrease eye velocity in the smooth pursuit test.

CONCLUSION

The prominent effects of the stronger central anticholinergic promethazine, on saccadic and smooth pursuit eye movements, potentially conveys the significance of central cholinergic pathways in the control of these centrally regulated oculomotor processes.

Scopolamine alleviates involuntary lingual movements: tardive dyskinesia or dystonia?

Cholinergic hypofunction was believed to be associated with the pathogenesis of tardive dyskinesia, and therefore, anticholinergic treatment might exacerbate the condition. We describe herein a middle-aged male with feeble chewing movements, involuntary rolling motions of the tongue, and abnormally tightened cheeks which developed after consuming different psychotropic medications. These symptoms did not improve after routine treatment for tardive dyskinesia, but responded well to anticholinergic agents, such as scopolamine and benzhexol hydrochloride. This case extended our understanding of the complexity of extrapyramidal effects and their pharmacologic management.

Anticholinergic activity in the nervous system: Consequences for visuomotor function

Acetylcholine is present in the peripheral and central nervous system, where it is involved in a number of fundamental physiological and biochemical processes. In particular, interaction with muscarinic receptors can cause adverse effects such as dry mouth, drowsiness, mydriasis and cognitive dysfunction. Despite the knowledge that exists regarding these common side-effects, little is known about how anticholinergic medications influence central motor processes and fine motor control in healthy individuals. This paper reviews critical visuomotor processes that operate in healthy individuals, and how controlling these motor processes are influenced by medications that interfere with central cholinergic neurotransmission. An overview of receptor function and neurotransmitter interaction following the ingestion or administration of anticholinergics is provided, before exploring how visuomotor performance is affected by anticholinergic medications. In particular, this review will focus on the effects that anticholinergic medications have on fixation stability, saccadic eye movements, smooth pursuit eye movements, and general pupil dynamics.

Striatal cholinergic interneurons and D2 receptor-expressing GABAergic medium spiny neurons regulate tardive dyskinesia

Tardive dyskinesia (TD) is a drug-induced movement disorder that arises with antipsychotics. These drugs are the mainstay of treatment for schizophrenia and bipolar disorder, and are also prescribed for major depression, autism, attention deficit hyperactivity, obsessive compulsive and post-traumatic stress disorder. There is thus a need for therapies to reduce TD. The present studies and our previous work show that nicotine administration decreases haloperidol-induced vacuous chewing movements (VCMs) in rodent TD models, suggesting a role for the nicotinic cholinergic system. Extensive studies also show that D2 dopamine receptors are critical to TD. However, the precise involvement of striatal cholinergic interneurons and D2 medium spiny neurons (MSNs) in TD is uncertain. To elucidate their role, we used optogenetics with a focus on the striatum because of its close links to TD. Optical stimulation of striatal cholinergic interneurons using cholineacetyltransferase (ChAT)-Cre mice expressing channelrhodopsin2-eYFP decreased haloperidol-induced VCMs (~50%), with no effect in control-eYFP mice. Activation of striatal D2 MSNs using Adora2a-Cre mice expressing channelrhodopsin2-eYFP also diminished antipsychotic-induced VCMs, with no change in control-eYFP mice. In both ChAT-Cre and Adora2a-Cre mice, stimulation or mecamylamine alone similarly decreased VCMs with no further decline with combined treatment, suggesting nAChRs are involved. Striatal D2 MSN activation in haloperidol-treated Adora2a-Cre mice increased c-Fos⁺ D2 MSNs and decreased c-Fos⁺ non-D2 MSNs, suggesting a role for c-Fos. These studies provide the first evidence that optogenetic stimulation of striatal cholinergic interneurons and GABAergic MSNs modulates VCMs, and thus possibly TD. Moreover, they suggest nicotinic receptor drugs may reduce antipsychotic-induced TD.

A Case Report on Dyskinesia Following Rivastigmine Patch 13.3 mg/24 hours for Alzheimer's Disease: Perspective in the Movement Disorders Spectrum Following Use of Cholinesterase Inhibitors

Current reports on movement disorder adverse effects of acetylcholinesterase inhibitors only include extrapyramidal symptoms and myoclonus.Here is a case of an 81-year-old female Filipino with dementia who presented with first-onset generalized choreiform movements.The etiology of the clinical finding of dyskinesia was investigated through laboratories, neuroimaging, and electroencephalogram, all of which yielded negative results. Review of her medications included the rivastigmine (Exelon) patch, which had just been increased to 13.3 mg/24-hour-dose 3 months prior. With all other possible causes excluded, a trial discontinuation of rivastigmine, showed decreased frequency of the dyskinesia 48 hours after, with complete resolution after 6 days, and no recurrence since then.This case thus presents a probable association or causality between the choreiform movement and rivastigmine at 13.3 mg/24-hour-dose patch because of clear temporal proximity, lack of alternative explanations, and a reversal of the dyskinesia upon medicament discontinuation.

Drug-induced movement disorders

Movement disorders are frequently a result of prescription drugs or of illicit drug use. This article focuses on prescribed drugs but briefly mentions drugs of abuse. The main emphasis is on movement disorders caused by dopamine receptor-blocking agents. However, movement disorders caused by other drugs are also briefly discussed.

Effects of discontinuing anticholinergic treatment on movement disorders, cognition and psychopathology in patients with schizophrenia

BACKGROUND

Physicians have prescribed anticholinergic agents such as benztropine, procyclidine, biperiden and trihexyphenidyl for treatment and prophylaxis of antipsychotic-induced extrapyramidal symptoms (EPS) for decades. Anticholinergic agents can however worsen tardive dyskinesia and cause many adverse effects, including cognitive impairment. Previous studies of anticholinergic discontinuation in patients with schizophrenia receiving antipsychotics have yielded a wide range of EPS relapse rates. Improvement in cognition after anticholinergic withdrawal was observed in some studies.

OBJECTIVE

This study evaluated the effect of anticholinergic discontinuation on movement disorders, cognition and general psychopathology after a 4-week taper in 20 outpatients with schizophrenia or schizoaffective disorder treated with antipsychotics.

RESULTS

Eighteen of twenty patients successfully discontinued their anticholinergic medication; two did not because of akathisia. Repeated measures analysis of variance did not show a significant effect of anticholinergic discontinuation on total Extrapyramidal Symptoms Rating Scale score or on the Parkinsonism, Akathisia, Dystonia or Tardive Dyskinesia subscales. However, significant improvement was found on the Brief Assessment of Cognition in Schizophrenia composite z score at weeks 6, 8 and 12 compared with baseline. Significant improvements were seen on the motor and the symbol-coding tasks. No significant effects were observed on the Positive and Negative Syndrome Scale, Clinical Global Impression - Severity and Clinical Global Impression - Improvement scales.

CONCLUSION

In this 12-week study of anticholinergic discontinuation in 20 outpatients with schizophrenia or schizoaffective disorder, gradual decrease and discontinuation of anticholinergics led to a positive effect on cognition. There were no adverse consequences on general psychopathology and no significant differences for 18 of 20 subjects on movement disorders.

Tardive dyskinesia in a South Asian population with first episode psychosis treated with antipsychotics

BACKGROUND

Tardive dyskinesia (TD) is a side effect of antipsychotic treatment that often only appears after months or years of treatment. A systematic review of randomized controlled trials lasting more than 1 year showed that second-generation antipsychotics (SGAs) were associated with an approximately fivefold lower risk of TD compared to haloperidol in patients with chronic schizophrenia. In contrast, there is little research on the risk of TD with other first-generation antipsychotics (FGAs), and this applies especially to their use in the treatment of patients with first episode psychosis (FEP).

OBJECTIVES

To determine the severity and point prevalence of TD in a naturalistic sample of patients with FEP in Pakistan treated with FGAs or SGAs.

METHODS

This was an observational study. TD was assessed by trained clinicians using the Abnormal Involuntary Movement Scale.

RESULTS

In the total sample (number =86) the mean age of patients was 26 years and the prevalence of TD (Schooler Kane criteria) was 29% with no significant difference between those treated with FGAs and SGAs (31% FGAs versus 26% SGAs; P=0.805). The Abnormal Involuntary Movement Scale total score (items 1-7), a measure of the severity of TD, was significantly higher for patients treated with FGAs versus those treated with SGAs (P=0.033). Scores on specific items showed that this reflected higher scores for dyskinesia affecting the muscles of facial expression, as well as of the upper and lower limb, whereas scores did not differ significantly in other body areas.

CONCLUSION

FGAs were associated with greater severity, though not prevalence, of TD than SGAs. The study highlights the relatively high rate of TD in Asian FEP patients and the need for clinicians to monitor for this and other potential antipsychotic side effects during treatment.

Anticholinergics in the era of atypical antipsychotics: short-term or long-term treatment?

Anticholinergic agents are usually prescribed to prevent or treat antipsychotic-induced extrapyramidal symptoms. Their long-term benefits are questionable and they carry diverse adverse effects, including cognitive impairment and worsening of tardive dyskinesia. This literature review explores the impact of anticholinergic medication discontinuation on movement disorders, cognition and psychopathology in patients receiving antipsychotics. Medline, Embase and PsycInfo were searched from 1950 to July 2011 using "cessation /withdrawal /discontinuation /stopping" with "anticholinergic*" or "antiparkinson*" and "neuroleptic*" or "antipsychotic*". Additional articles were obtained by searching the bibliographies of relevant references. Earlier studies of anticholinergic agent discontinuation in patients receiving first-generation antipsychotics reported relapse rates of extrapyramidal symptoms between 4% and 80%, reflecting the heterogeneity of the studies. Two recent studies of patients prescribed second-generation antipsychotics obtained relapse rates of 4% and 33%. Some studies suggest improvement in tardive dyskinesia with cessation of anticholinergics. Four studies examined the effects of anticholinergic agent discontinuation on cognition and all observed an improvement post-discontinuation. Changes in symptoms of schizophrenia with anticholinergic discontinuation are conflicting, with more recent studies suggesting an improvement. Given their questionable benefit with continued use, clinicians should consider a gradual withdrawal of anticholinergic agents in stable patients receiving antipsychotics.

Extrapyramidal motor side-effects of first- and second-generation antipsychotic drugs

BACKGROUND

Second-generation antipsychotics have been thought to cause fewer extrapyramidal side-effects (EPS) than first-generation antipsychotics, but recent pragmatic trials have indicated equivalence.

AIMS

To determine whether second-generation antipsychotics had better outcomes in terms of EPS than first-generation drugs.

METHOD

We conducted an intention-to-treat, secondary analysis of data from an earlier randomised controlled trial (n = 227). A clinically significant difference was defined as double or half the symptoms in groups prescribed first- v. second-generation antipsychotics, represented by odds ratios greater than 2.0 (indicating advantage for first-generation drugs) or less than 0.5 (indicating advantage for the newer drugs). We also examined EPS in terms of symptoms emergent at 12 weeks and 52 weeks, and symptoms that had resolved at these time points.

RESULTS

At baseline those randomised to the first-generation antipsychotic group (n = 118) had similar EPS to the second-generation group (n = 109). Indications of resolved Parkinsonism (OR = 0.5) and akathisia (OR = 0.4) and increased tardive dyskinesia (OR = 2.2) in the second-generation drug group at 12 weeks were not statistically significant and the effects were not present by 52 weeks. Patients in the second-generation group were dramatically (30-fold) less likely to be prescribed adjunctive anticholinergic medication, despite equivalence in terms of EPS.

CONCLUSIONS

The expected improvement in EPS profiles for participants randomised to second-generation drugs was not found; the prognosis over 1 year of those in the first-generation arm was no worse in these terms. The place of careful prescription of first-generation drugs in contemporary practice remains to be defined, potentially improving clinical effectiveness and avoiding life-shortening metabolic disturbances in some patients currently treated with the narrow range of second-generation antipsychotics used in routine practice. This has educational implications because a generation of psychiatrists now has little or no experience with first-generation antipsychotic prescription.

A survey of the tardive dyskinesia induced by antipsychotic drugs in patients with schizophrenia

OBJECTIVE

Tardive Dyskinesia (TD), is one of the important problems of the patients with schizophrenia. The emergence of these side effects depends on so many factors such as the patients' age and the duration of antipsychotic treatment. By discovering new drugs (Atypical), there has been an outstanding decrease in the emergence of these side effects. The present study investigates the symptoms of TD in the Patients with schizophrenia who were under treatments for more than 6 months.

METHOD

The sample of this study was 200 Patients with schizophrenia of four wards in Razi hospital (two acute and two chronic wards) who were hospitalized in the winter of 2006 and were qualified for this study. The subjects were 101 males and 99 females who were younger than 60 and had received antipsychotic drugs for at least 6 months. After psychiatric interview and filling the demographic questionnaire by the patients, the required information about the drugs and the intensity of the symptoms was acquired. Then clinical and physical examinations of tardive dyskinesia were done. Next, the tardive dyskinesia disorders' check list (AIMS) was used. Findings of this cross-sectional, descriptive study were analyzed by SPSS.

RESULTS

There was a high ratio of 95% between TD and the age factor (P=0.05). There was no relationship between symptoms frequency and duration of treatment (P=0.68). Facial muscles and oral zones were mostly involved in T.D disorder (72%).

CONCLUSION

No significant difference was observed between nine fold symptoms of T.D in patients who were using traditional drugs and those who were using the new ones (typical and atypical). Findings showed that in the intensity of the symptoms, gender does not play a major role.

Anticholinergic agents can induce oromandibular dyskinesia

Background and Purpose:

Oromandibular dyskinesia (OMD) can occur spontaneously or they can be induced by the conventional dopamine receptor antagonists. Anticholinergic medications have rarely been reported to cause OMD in parkinsonian or non-parkinsonian patients.

Methods:

We analyzed the clinical features of two parkinsonian and one non-parkinsonian patients who experienced OMD after anticholinergic medication.

Results:

Each patient of our cases developed oromandibular symptoms in the temporal regions that were related to the addition of anticholinergic agents, and the symptoms were relieved following the discontinuation of the causative anticholinergic drugs. In one of our case, levodopa alone did not cause dyskinesia but augmented dyskinesia associated with anticholinergics.

Conclusions:

Here we report two parkinsonian and one non-parkinsonian patients with OMD induced by the use of anticholinergic agents. In our cases, we could not find any other precipitating or actual secondary causes for the OMD symptoms in our patients. Furthermore, the fact that the OMD in our cases were ameliorated with cessation of anticholinergics suggests that it may be anticholinergic-induced.

Focus on lower risk of tardive dyskinesia with atypical antipsychotics

BACKGROUND

Tardive dyskinesia (TD) is one of the most serious iatrogenic neurological complications of the first-generation antipsychotics. Identifying the risk factors for TD is important to minimize the risk of this potentially irreversible movement disorder in susceptible populations.

METHODS

A Medline search was conducted for the literature on risk factors for TD with the first-generation antipsychotics, as well as the emerging literature of the lower risk of TD with the second-generation antipsychotics.

RESULTS

Several demographic, phenomenological, comorbidities and treatment variables have been reported to be associated with higher risk of TD. On the other hand, significantly lower rates of TD have been reported with the second-generation atypical antipsychotics, even in high risk groups such as the elderly.

CONCLUSIONS

The use of the second-generation antipsychotics as first-line treatment of psychosis appears to have lowered the overall prevalence of acute movement disorders as well as TD, and have led them to become the standard of care in part because of their safer extrapyramidal profiles.

Systematic review of cholinergic drugs for neuroleptic-induced tardive dyskinesia: a meta-analysis of randomized controlled trials

The authors evaluated the efficacy of cholinergic drugs in the treatment of neuroleptic-induced tardive dyskinesia (TD) by a systematic review of the literature on the following agents: choline, lecithin, physostigmine, tacrine, 7-methoxyacridine, ipidacrine, galantamine, donepezil, rivastigmine, eptastigmine, metrifonate, arecoline, RS 86, xanomeline, cevimeline, deanol, and meclofenoxate. All relevant randomized controlled trials, without any language or year limitations, were obtained from the Cochrane Schizophrenia Group's Register of Trials. Trials were classified according to their methodological quality. For binary and continuous data, relative risks (RR) and weighted or standardized mean differences (SMD) were calculated, respectively. Eleven trials with a total of 261 randomized patients were included in the meta-analysis. Cholinergic drugs showed a minor trend for improvement of tardive dyskinesia symptoms, but results were not statistically significant (RR 0.84, 95% confidence interval (CI) 0.68 to 1.04, p=0.11). Despite an extensive search of the literature, eligible data for the meta-analysis were few and no results reached statistical significance. In conclusion, we found no evidence to support administration of the old cholinergic agents lecithin, deanol, and meclofenoxate to patients with tardive dyskinesia. In addition, two trials were found on novel cholinergic Alzheimer drugs in tardive dyskinesia, one of which was ongoing. Further investigation of the clinical effects of novel cholinergic agents in tardive dyskinesia is warranted.

Cholinergic medication for neuroleptic-induced tardive dyskinesia

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

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

MAIN RESULTS

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

REVIEWER'S CONCLUSIONS

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

A review of the assessment of dyskinesias

Dyskinesias are most prevalent in patients with Huntington's disease (HD), patients with Parkinson's disease (PD) who have received chronic levodopa therapy, and in patients who have been treated with neuroleptics (tardive dyskinesia ITD]). Recent therapeutic developments have fueled a growing interest in the clinimetrics of dyskinesias. For dyskinesias in HD, few rating scales are available, but data on validity, reliability, and responsiveness are scarce. Only the interrater reliability of facial dyskinesias has been evaluated and found to be low. Many subjective rating scales for dyskinesias in PD exist, but only the Dyskinesia Rating Scale has undergone sufficient clinimetric evaluation. For TD, numerous rating scales are available, many of them with ample data on reliability and validity. Objective assessment of dyskinesias has been attempted with a number of techniques. All these methods require a laboratory setting, rendering them susceptible to influence of stress. Moreover, they provide only a momentary assessment of dyskinesia severity and fail to take into account diurnal fluctuations. In view of the methodologic shortcomings in the assessment of dyskinesias, more effort needs to be put into strengthening currently available modes of assessment or designing new ones. In the future ambulatory accelerometry might prove to be of value in this field.

Extrapyramidal syndromes in neuroleptic-treated patients: prevalence, risk factors, and association with tardive dyskinesia

Prevalence and risk factors for extrapyramidal syndromes (EPS) were investigated in a sample of 1,559 patients. The overall prevalence of EPS was 29.4% (N = 458). Among the EPS-diagnosed patients, parkinsonism as assessed by the presence of core parkinsonian symptoms (rigidity, tremor, bradykinesia) was present in 65.9% of patients (N = 302), akathisia in 31.8% (N = 145), and acute dystonia in 2.1% (N = 10). Old age and long-term neuroleptic drug (NL) treatment were significantly associated with EPS in both the univariate and the multivariate analyses, whereas no relationship was observed with average NL daily doses and current NL treatment. EPS was diagnosed in 50.2% of 285 patients with persistent tardive dyskinesia (TD). Distribution of EPS in patients with TD showed that tremor and akathisia were more frequent in peripheral TD cases than in orofacial TD cases. Furthermore, there was a stronger association of NL-induced parkinsonism with peripheral TD than with orofacial TD. This study suggests that the association between EPS and TD may be limited to specific subtypes of TD. Peripheral TD showed a higher association with parkinsonism and with akathisia, suggesting that these symptoms may share a common pathophysiology.

Pharmacological options for the management of dyskinesias

Dyskinesias are abnormal involuntary movements characterised by an excessive amount of movement. Typically, these movements are choreiform in nature. They may be caused by systemic, metabolic, endocrinologic, structural, vascular, infectious or inherited degenerative conditions, or be toxin- or drug-induced. With many non-drug-induced dyskinesias, treatment of the underlying condition may be sufficient to eliminate the movements, although temporary treatment may be required to control the movements if they are severe. Drug-induced dyskinesias often resolve when the offending drug is discontinued. A notable exception is tardive dyskinesia, which is caused by exposure to dopamine receptor blocking drugs, the majority of which are antipsychotic agents. Tardive dyskinesias will persist, or may even develop after the causative agent has been stopped and may not spontaneously remit. Another commonly encountered form of drug-induced dyskinesia is seen in patients with Parkinson's disease who are receiving levodopa. Medications which deplete dopamine are most successful in treating choreiform dyskinesias, although anticholinergics, GABAergics, serotonergics, and calcium channel blocking agents have been reportedly beneficial in some cases. Treatment of levodopa-induced dyskinesias requires manipulation of the patient's antiparkinsonian drug regimen.

Risk factors for orofacial and limbtruncal tardive dyskinesia in older patients: a prospective longitudinal study

Although there is a consensus that orofacial and limbtruncal subtypes of tardive dyskinesia (TD) exist and may represent distinct pathophysiologic entities, few studies have examined the incidence of and risk factors associated with the development of these TD subtypes. Two hundred and sixty-six middle-aged and elderly outpatients with a median duration of 21 days of total lifetime neuroleptic exposure at study entry were evaluated at 1- to 3-month intervals. Using "mild" dyskinesia in any part of the body for diagnosis of TD, the cumulative incidence of orofacial TD was 38.5 and 65.7% after 1 and 2 years, respectively, whereas that of limbtruncal TD was 18.6 and 32.6% after 1 and 2 years. Preclinical dyskinesia was predictive of both orofacial and limbtruncal TD. History of alcohol abuse or dependence was a significant predictor of orofacial TD only whereas tremor was a significant predictor of limbtruncal TD only. Findings support suggestions that orofacial and limbtruncal TD may represent specific subsyndromes with different risk factors.

Dyskinesias following treatment with 5-HT re-uptake inhibitors

Three cases of dyskinesia attributable to selective serotonergic antidepressant drugs are presented. The patients were not on other medication nor had they been in preceding weeks. The movement disorder disappeared on cessation of the drug within a time period corresponding to the expected wash-out for the different preparations. The emergence of dyskinesic symptoms coincided with a significant deterioration in mental state after an initial good response to the particular medication. Considering the apparently selective action of the serotonin re-uptake inhibitors, these cases suggest that movement disorders and psychiatric symptoms are unlikely to be due to single neurotransmitter mechanisms and that a disturbance of the balance between the different systems is a more likely hypothesis.

Loss of striatal cholinergic neurons as a basis for tardive and L-dopa-induced dyskinesias, neuroleptic-induced supersensitivity psychosis and refractory schizophrenia

In the first section of this paper several aspects of tardive dyskinesia (TD) (clinical, epidemiological, pharmacological) are reviewed. We propose that this syndrome is not the consequence of dopamine receptor proliferation, but results from damage or degeneration of striatal cholinergic interneurons. We suggest that this cellular damage is caused by prolonged overactivation of these neurons, which occurs when they are released from dopaminergic inhibition following neuroleptic administration. Overactivity of central cholinergic systems during akinetic and motor retarded depression could be a contributory cause. The predisposition to L-DOPA-induced peak-dose dyskinesia in Parkinson's disease may depend on the same type of striatal neuronal loss. In the second part of the paper, the subject of supersensitivity psychosis and drug-resistant schizophrenia is reviewed. These two syndromes, are commonly associated with TD, have similar predisposing factors and pharmacology to TD, and are potentially persistent. We suggest that these conditions also result from degeneration of cholinergic striatal interneurons following chronic neuroleptic administration. The efficacy of clozapine for such treatment-refractory psychoses is explained in terms of its blockade of D-1 dopamine receptors. Other drugs effective against refractory psychoses (e.g. risperidone) are predicted to reduce activation at D-1 receptors.

Orobuccal dyskinesia associated with trihexyphenidyl therapy in a patient with Parkinson's disease

Dyskinesia is a common adverse effect complicating chronic dopaminergic therapy for Parkinson's disease. Movements are frequently choreic in nature and have been ascribed to overstimulation of "supersensitive" striatal postsynaptic dopamine receptors. Anticholinergic medications, despite some clinical efficacy in Parkinson's disease, have rarely been reported to cause dyskinesia. We report a patient with Parkinson's disease who developed orobuccal dyskinesia while being treated with trihexyphenidyl (Artane). Dyskinesia was observed following the introduction of trihexyphenidyl, resolved with its discontinuation, and reappeared with its reinstitution. Carbidopa-levodopa (Sinemet) alone did not cause dyskinesia but augmented dyskinesia associated with trihexyphenidyl.

Treatment of schizophrenia: a clinical and preclinical evaluation of neuroleptic drugs

Forty years after the first clinical report on the effectiveness of chlorpromazine in psychiatric patients, neuroleptic drugs are still the most widely used drugs in the treatment of schizophrenia. Indeed, there are no other drugs which have proven to be as effective in the treatment of this severe psychiatric disorder. Yet, there are still many unresolved problems relating to neuroleptic drugs. The present review gives a comprehensive overview of our knowledge (and our lack of knowledge) with respect to the clinical and preclinical effects of neuroleptic drugs and tries to integrate this knowledge in order to identify the neuronal mechanisms underlying the therapeutic and side effects of neuroleptic drugs.

Persistent tardive dyskinesia: demographic and pharmacological risk factors

The demographic, clinical and pharmacological risk factors for persistent tardive dyskinesia (TD) were investigated in a sample of 1745 patients. When simultaneously adjusting for the effects of demographic and pharmacological factors using multivariate logistic regression, female sex and advanced age were positively and significantly associated with increased risk of TD. Interaction between these two variables, investigated by cross-stratification, was significant. Furthermore, high neuroleptic dose and concomitant use of neuroleptic and antiparkinsonian drugs were both significantly associated with increased risk of TD. The results support the view that both vulnerability factors and high neuroleptic doses contribute to the occurrence of TD and further stress the relevance of a conservative use of antipsychotic medication, particularly in older women.

Intravenous benztropine and propranolol challenges in tardive akathisia

We challenged five patients suffering from tardive akathisia (TA) with intravenous benztropine (2 mg), propranolol (1 mg) and placebo (saline) using a random, double-blind cross-over design to examine the effects of the drugs on the subjective, objective and global manifestations of neuroleptic-induced akathisia. Benztropine produced a marginally significant, and propranolol a significant improvement in the overall manifestations of the disorder. The patients demonstrated a considerable placebo effect and marked variation in their responses to the drugs. The implications of these findings for the pathophysiology of TA in relation to acute akathisia and tardive dyskinesia are discussed.

Sub-syndromes of tardive dyskinesia and some clinical correlates

Syndromes of dyskinetic movements in subjects (N = 70) with chronic schizophrenia were investigated, using principal components analysis of AIMS ratings. Consonant with previous research, three discrete groupings were found, namely dyskinetic movements of lips-jaw-tongue, limb-truncal and facial movements. These were then related to demographic, psychological and movement disorder variables. The limb-truncal, but neither the lips-jaw-tongue nor facial movements components, were associated with negative symptoms and cognitive impairment.

Risk factors for neuroleptic-induced movement disorders

Chronic neuroleptic therapy may be associated with the development of diverse movement disorders including Tardive dyskinesia (TD), Parkinsonism, dystonia, and akathisia in a subset of schizophrenic patients. It is presently unknown why only a proportion of neuroleptic-treated patients develop these movement disorders. In the following communication, we present a series of studies which demonstrate that the development of these movement disorders may be facilitated by certain risk factors including disturbances in pineal melatonin functions, diabetes mellitus, cognitive deficits, suicidal behavior, and disturbances in the functions of the choroid plexus. Recognition of these biological factors may prove useful in: (a) further understanding of the pathophysiology of these disorders, and (b) identifying patients at risk for these movement disorders.

The psychological consequences of tardive dyskinesia. The effect of drug-induced parkinsonism and the topography of the dyskinetic movements

The effect of drug-induced Parkinsonism and of the topography of the dyskinetic movements on the psychological consequences of tardive dyskinesia was assessed in 20 schizophrenic subjects and 20 non-dyskinetic schizophrenic controls matched for age, sex, the presence of anticholinergic medication, and the presence and severity of drug-induced Parkinsonism. Limb-truncal subscale scores but not orofacial scores had a significant correlation with cognitive impairment and with negative symptoms. Drug-induced Parkinsonism was found to be a powerful confounding variable.

Neurochemical changes associated with the persistence of spontaneous oral dyskinesia in rats following chronic reserpine treatment

Rats treated chronically with reserpine develop spontaneous oral dyskinesia. The present study examined the development of the oral dyskinesia during the course of reserpine treatment, and its persistence after termination of treatment. Rats were injected with either reserpine (1 mg/kg, s.c.) or vehicle once daily for 4 days and then every other day for 6 weeks. Oral dyskinesia developed rapidly, reaching a maximal level after 3 days. It persisted at a maximal level for up to 20 days after termination of reserpine treatment, and continued to persist above control level for at least 60 days. The reserpine-treated rats also exhibited stereotypy in response to acute injection of the D1-selective agonist SKF-38393 (10 mg/kg), which was not observed in control rats. In contrast to the oral dyskinesia, this altered sensitivity to SKF-38393 returned to normal within 20 days after terminating the reserpine treatment, suggesting that these two behavioral responses involve different neural mechanisms. Quantitative autoradiographic measurement of dopamine receptor subtypes revealed that both D1 and D2 receptors were increased in the caudate-putamen (Cpu) and nucleus accumbens. Only the increase in D2 receptor density in the CPu correlated with the persistence of the oral dyskinesia; both changes persisted following termination of the reserpine treatment, and their magnitude was less at 60 days than at 1 and 20 days post-treatment. These results may have important implications for tardive dyskinesia.

The relationship of tardive dyskinesia to positive schizophrenia

Investigations aimed at identifying the clinical characteristics that discriminate Tardive dyskinesia (TD) from non-TD patients have yielded disparate findings. A number of studies have suggested that TD may be a feature of negative schizophrenia. In particular, the association of TD with high prevalence of "soft" neurological signs, cognitive deficits, and abnormal brain morphology on CT scan in some patients, have led several investigators to propose that negative schizophrenia may be a risk factor for TD. The neurochemical profile of TD, however, is not consistent with this hypothesis. In the following communication, we present our studies which suggest that TD is specific to and an intergral part of positive schizophrenia. The data suggest that schizophrenic patients with predominant positive symptoms may be at increased risk for the development of TD. In addition, we present evidence linking TD with left cerebral hemispheric dysfunction. By comparison, we provide evidence that negative schizophrenia is related to diencephalic damage, and discuss its relevance to negative schizophrenia and to Parkinsonism. We also provide evidence that negative schizophrenia may be a risk factor for acute drug-induced dystonia. Thus, these findings are consistent with our model that negative schizophrenia is a risk factor for Parkinsonism, whereas positive schizophrenia is related to TD. In analogy with the positive/negative dichotomy of schizophrenia, we propose that TD could be considered a "positive," where Parkinsonism a "negative" movement disorder.

Pharmacological characterization of tardive akathisia

A patient with tardive neuroleptic-induced akathisia was investigated with multiple pharmacological challenges. It was noted that the patient responded positively to benztropine, bromocriptine, and propranolol, and negatively to physostigmine, and showed little or no response to discontinuation of neuroleptics and challenges with metoclopramide, metoprolol, atenolol, and clonidine. The implications of this pharmacological characterization for the understanding of the pathophysiology of tardive akathisia in relation to acute akathisia and tardive dyskinesia are discussed.

Relationship of psychotic symptoms to haloperidol-stimulated prolactin release

Prolactin (PRL) response to a single dose of intravenous haloperidol (0.5 mg) was measured as a marker of tuberoinfundibular dopamine (TIDA) activity in 24 neuroleptic-free, male, psychotic patients. The PRL responses were then correlated with psychotic symptoms measured with Andreasen's Scales for the Assessment of Positive and Negative Symptoms (SAPS, SANS). Correlation analyses revealed a significant inverse relationship between PRL response and the severity of delusional symptoms. There was no significant correlation between the symptoms of hallucinations, formal thought disorder, or global negative symptoms and PRL response to haloperidol, nor were there any significant correlations between basal PRL and symptom severity. These results suggest that among the positive and negative symptoms associated with psychoses, only delusions may be associated with TIDA overactivity.

Dopaminergic alterations in cotreatments attenuating haloperidol-induced hypersensitivity

Chronic treatment of the laboratory rat with haloperidol results in an increased stereotypic behavioral response to subsequent dopamine agonist challenge. This behavioral hypersensitivity (BH) is thought to reflect an increase in DA receptor number following chronic pharmacologic denervation. Using a cotreatment strategy, we demonstrate here that a variety of agents can attenuate or prevent the development of BH when administered chronically with haloperidol. Cotreatment with lithium and amantadine prevented the changes in DA biochemistry as well as the proliferation of DA receptors normally associated with chronic haloperidol treatment. Cotreatment with thioridazine or scopolamine did alter the changes in DA biochemistry normally associated with haloperidol treatment, but failed to attenuate the DA receptor proliferation. Taken together, these data suggest that mechanisms in addition to DA biochemical and receptor changes participate in the development and subsequent expression of BH. DA receptor proliferation must, therefore, be considered permissive to the development of BH.

D1 and D2 dopamine receptor interactions with pilocarpine-induced oral activity in rats

To investigate the relationship between dopamine (DA) and acetylcholine (ACh) systems in the control of oral movement, we studied the effects of specific D1 and D2 drugs on vacuous chewing movements induced by the muscarinic ACh agonist, pilocarpine. In previous experiments we found that when given alone, the D1 agonist SKF 38393 increased vacuous chewing and the D1 antagonist SCH 23390 decreased it, while both the D2 agonist LY 171555 (quinpirole) and the D2 antagonist sulpiride decreased vacuous chewing. In the present experiment, the effects of the D1 drugs had similar effects in rats concurrently given pilocarpine. In contrast, the effects of both of the D2 drugs were altered by pilocarpine. Surprisingly, the actions of D2 agonist and antagonist were affected in opposite ways. The effect of sulpiride in reducing oral movement activity was eliminated by pilocarpine, while the effect of LY 171555 in reducing oral movement was enhanced by pilocarpine.

Chronic neuroleptic-induced mouth movements in the rat: suppression by CCK and selective dopamine D1 and D2 receptor antagonists

Fluphenazine decanoate (25 mg/kg IM every 3 weeks x 6) resulted in spontaneous vacuous chewing mouth movements and jaw tremor in male Sprague-Dawley rats. These movements could be suppressed by the selective D1 or D2 dopamine antagonists SCH 23390 (0.5 mg/kg) and raclopride (0.5 mg/kg), respectively, and by CCK-8S (50 micrograms/kg). Fluphenazine-induced mouth movements were unaffected by the selective CCK antagonist MK-329, and by a dose of physostigmine (50 micrograms/kg) sufficient to stimulate mouth movements in placebo treated rats. Scopolamine (0.1 mg/kg) suppressed spontaneous mouth movements in placebo-treated rats, but the effect on fluphenazine-induced mouth movements was not significant. A higher dose of scopolamine (0.5 mg/kg) did suppress the neuroleptic-induced mouth movements, but also induced hyperactivity, characterized by increased sniffing and grooming. These findings indicate that mouth movements resulting from the chronic administration of neuroleptics to the rat may serve as a useful pharmacological model of tardive dyskinesia in the human, and suggest that a relative increase of D1 activity as well as impaired CCK function may contribute to the pathogenesis of this disorder.

Recognition and differential diagnosis of tardive dyskinesia

Tardive dyskinesia (TD) is a consequence of chronic neuroleptic therapy. It is an irregular stereotyped movement disorder that is usually choreic in appearance, and is subject to temporary volitional control. Dystonia, akathisia, and tics are uncommon variants of the classic tardive syndrome. Characteristic clinical features including amelioration by action, augementation by distraction, partial volitional suppressibility, and lack of subjective distress help differentiate TD from other movement disorders such as resting tremor, Huntington's disease, spontaneous dyskinesias, and abnormal movements accompanying psychiatric illnesses.

Masticatory muscle hyperactivity in temporomandibular disorders: is it an extrapyramidally expressed disorder?

Masticatory muscle hyperactivity appears to have an important role in temporomandibular disorders. A pathophysiological model for masticatory muscle hyperactivity is proposed that is centrally mediated, yet maintains support for present peripheral causes and therapies. In this hypothesis, masticatory muscle hyperactivity represents a mild extrapyramidal disorder distantly related to orofacial dyskinesias. Experimental evidence suggests a neurotransmitter imbalance in the basal ganglia, involving dopaminergic preponderance, or cholinergic and GABA-nergic hypofunction as the underlying cause.