|dc.description.abstract||An overview of the varied clinico-neurological features of dyskinesias in
general is presented, and literature an the epidemiology af tardive dyskinesia since the introduction of antipsychotic drugs in 1950, reviewed. Furthermore reasons for the wide variations in previously
published prevalence figures have been critically highlighted, and
suggestions based upon the current state of clinical and experimental
knowledge put forward concerning the pathogenesis of drug induced
The type and prevalence of abnormal or purposeless involuntary movements has been surveyed among a large sample of long term White patients
resident in Town Hill Hospital for a period of not less than 4 years, mast af whom were either currently receiving or had received neuroleptic
medication. This sample comprised 190 men and 98 women whose ages ranged from the third to the ninth decade. Patients manifesting abnormal
movements were grouped into 5 general diagnostic categories for analysis viz. schisophrenic disorders, affective disorders, organic brain disorders and syndromes, defective mental development and discrete
neurological disorder. The movements were clinically classified in terms
cf the areas of the body involved and semi quantitatively measured according to a standardised duration rating scale procedure.
Involuntary movements were noted to be present in a total o-f 83 patients examined, most o-f which were adjudged to correspond to the syndrome currently termed 'tardive dyskinesia'. Subtype analysis o-f movement
distribution indicated that 277. of cases manifested classical oro-facial
dyskinesia while 527. showed body dyskinesia o-f the type designated
' pseudaakathisia'; the balance o-f the patients presented combinations o-f
the two types.
Schizophrenic disorders constituted the commonest diagnostic category in the dyskinesia group up to the fifth decade. Functionally obtrusive
involuntary movements were observed in only some 77. of the patients with
dyskinesia. Prevalence overall was equal between the sexes, and no
correlations were discerned between age, sex, diagnosis or dyskinesia
subtype of cases and the rating scores obtained.
Prevalence rates obtained by this survey are favourably low by comparison with many results of overseas investigators, and are similar in this
respect to figures reported in the very few prevalence studies carried
out to date in South African institutions.||en_US