To the Editor.—
Tardive dyskinesia (TD) is an iatrogenic disorder related to neuroleptic (NL) drug exposure and is characterized by orofacial and lingual dyskinesias, often associated with choreiform movements of the extremities and trunk. Particular attention has been paid to early detection and accurate measurement of TD, considering that dose reduction and discontinuation of NL drug therapy are the only effective strategies for treating dyskinetic movements.Estimates of prevalence of TD in patients vary between 5% and 50%, with an average of about 20%.1 Several factors can account for the variability in TD prevalence: (1) fluctuating nature of the symptoms over time; (2) difference in method of assessment of the disorder (nominal vs ordinal criteria); and (3) difference in sociodemographic and clinical characteristics of the sample studied (age, duration and severity of illness, diagnosis).The aim of the present study was to measure the prevalence of TD in Italy. A