New Nomenclature for Drug-Induced Movement Disorders Including Tardive Dyskinesia

Psychotropic agents are increasingly being prescribed by different specialty clinicians for a varietyof psychiatric illnesses, making it necessary to improve understanding of the etiology, diagnosis, andmanagement of drug-induced movement disorders (D-IMD) across medical specialties. Early descriptionsof movement disorders were based on identifiable disease states such as parkinsonism, dystoniadeformans, and Huntington’s chorea, which introduced complicated and often overlapping nomenclature.This has hindered communication about, description of, and diagnosis of these drug-induceddisorders. Research criteria for tardive dyskinesia, a specific, purposeless, involuntary, hyperkinetic,potentially persistent D-IMD, have varied, with relatively few data-driven conclusions available tosupport clinical decision-making. The differences in research criteria among published reports onrates of tardive dyskinesia with atypical antipsychotics make it difficult to find meaningful comparisonsand conclusions between atypicals. A novel system for classifying D-IMD according to whetherthey are reversible or persistent, hypokinetic or hyperkinetic, and dystonic or nondystonic is proposed.This new classification system will provide clinicians and researchers across specialties a moreprecise language, which will hopefully improve the diagnosis of and research criteria for D-IMD.