The nosology of tardive parkinsonism.

Tardive parkinsonism (TP) is an ill-defined entity included in the category of drug-induced tardive syndromes in the DSM-V-TR. It refers to "persistent/permanent" previously developed iatrogenic parkinsonism following discontinuation of the offending drugs, mainly dopamine receptor antagonists. However, this definition appears incomplete not fully detailing the clinical course and the long-term outcome of the syndrome. The definition of "persistent/permanent non-progressive" seems more adequate allowing to differentiate TP from a progressive condition as Parkinson's disease, which may be sometimes unmasked by prolonged exposure to the same drugs. This proposal has been based on the persistence without progression of a parkinsonian syndrome five years on average following discontinuation of cinnarizine and flunarizine in most of our case series of elderly patients. Whether a permanent non-progressive parkinsonism may occur in elderly patients also following discontinuation of other dopamine receptor antagonists as antipsychotics and benzamide derivatives remains to be established due to lack of comparable prospective follow-up studies. The recognition of TP in elderly patients is important since it has a more favourable long-term prognosis than Parkinson's disease.