Mohammed T. Abou-Saleh

Principles and Practice of Geriatric Psychiatry.Editors: Professor John R. M. Copeland, Dr Mohammed T. Abou-Saleh and Professor Dan G. BlazerCopyright & 2002 John Wiley & Sons LtdPrint ISBN 0-471-98197-4 Online ISBN 0-470-84641-096Risk Factors for Dyskinesia in the ElderlyThomas R. E. BarnesImperial College School of Medicine, London, UKTARDIVE DYSKINESIAClinical FeaturesIn the mid-1950s, within a few years of the introduction ofantipsychotic drugs, clinicians drew attention to ‘‘neurotoxicreactions’’ to this treatment. In addition to parkinsonian features,involuntary orofacial movements were noted 1,2 . Sigwald et al. 3 areusually credited with the first detailed description of ‘‘facio-buccolinguomasticatorydyskinesia’’ associated with these drugs. In theearly 1960s, Faurbye et al. 4 coined the term ‘‘tardive dyskinesia’’for this condition.Abnormal involuntary orofacial movements remain the mostfamiliar and prevalent features of tardive dyskinesia. The movementsare irregular, stereotyped and choreic in nature, and tend toinvolve the tongue, lips, jaw and face, including the peri-orbitalareas. The movements observed include protrusion or twisting ofthe tongue, lip smacking, cheek puffing, pursing and suckingactions of the lips, and chewing and lateral jaw motions. Theparticular combinations of movement seen vary considerablybetween patients but tend to be relatively consistent for eachindividual.In addition to these orofacial phenomena, most descriptions oftardive dyskinesia include a variety of trunk and limb movements.These are typically choreiform or choreoathetoid in type,although athetosis of extremities, and axial and limb dystonia,are often listed as part of the syndrome, as are abnormalities ofgait and trunk posture, such as lordosis, rocking and swaying,shoulder shrugging and rotary movements of the pelvis. Gruntingand respiratory arrhythmias are also seen.The notion that orofacial and limb and trunk dyskinesiarepresent distinct pathophysiological entities with different riskfactors and clinical correlates 5 seems to hold true in olderpatients 6 . For example, Paulsen et al. 7 studied middle-aged andelderly outpatients starting antipsychotic drug treatment andobtained systematic follow-up data over 2 years. They found thatthe cumulative incidences and the significant predictors identifieddiffered for the two subsyndromes.Prevalence, Incidence and Natural HistoryWhile tardive dyskinesia is a common problem in thoseindividuals receiving antipsychotic drug treatment long-term, themajority will not exhibit the condition. The reported prevalencefigures vary widely, from 0.5% to 56% 8,9 , reflecting variables suchas the age of the sample studied (see below) and the sensitivity ofthe rating instrument used. Overall, the literature suggests thatonly 20% or so of drug treated patients will develop the problem,and of these, the dyskinesia is likely to be serious in less than 10%.Gardos et al. 10 concluded that the severe tardive dyskinesia is veryuncommon, occurring in approximately 1/100–1/1000 patientswith the condition. Nevertheless, in elderly psychiatric inpatients,prevalence figures of around 50% or greater are not uncommonlyreported 6 .The prospective study of Kane et al. 11,12 suggested that newcases of tardive dyskinesia can occur at a rate of 3–4% a year inthe first few years after starting antipsychotic medication.However, there is only limited information available to guidethe clinician as to who might be most at risk. Tardive dyskinesiawas originally considered irreversible, although follow-upstudies 13,14 have revealed that it is not a progressive disorder,but rather tends to fluctuate in severity over time. Spontaneousremissions are relatively common, particularly in youngerpatients. Such a view of the natural history of tardive dyskinesiain patients on chronic drug treatment was reinforced by the resultsof two 10 year follow-up studies by Yagi and Itoh 15 and Caseyand Gardos 16 .To some degree, these findings might be seen as relativelyreassuring, allaying earlier fears that tardive dyskinesia was amajor iatrogenic condition that would constrain the use of longtermantipsychotic drug therapy. However, while the conditionitself is rarely disabling, it can be socially stigmatizing. Further,severe tardive dyskinesia can be a troublesome problem,particularly in the elderly. Orofacial dyskinesia can interferewith eating and swallowing, render speech unintelligible, andcause breathing difficulties, sometimes leading to dysphagia orchoking 17–19 . Trunk and limb dyskinesia may be associated withdisturbances of gait that can lead to falls and injury 20 .RISK FACTORSAdvancing AgeIn numerous studies, advancing age has been clearly shown to bea major vulnerability factor for tardive dyskinesia. It is associatednot only with an increased occurrence of tardive dyskinesia butalso with greater severity and a reduced likelihood of spontaneousremission 9,21 . Studies involving geriatric patients have consistentlyfound a higher incidence of tardive dyskinesia with conventionalantipsychotics, even at low doses 22,23 . Examining pooled epidemiologicaldata has revealed a strong linear correlation betweenage and both the prevalence and severity of tardive dyskinesia 24 .However, duration of exposure to antipsychotic drugs is aconfounding variable, as older patients are likely to have receivedPrinciples and Practice of Geriatric Psychiatry, 2nd edn. Edited by J. R. M. Copeland, M. T. Abou-Saleh and D. G. Blazer&2002 John Wiley & Sons, Ltd