Am J Psychiatry 1977; 134:781-784
Copyright © 1977 by American Psychiatric Association
The relationship between parkinsonism and tardive dyskinesia
J Gerlach
The author analyzes parkinsonism and hyperkinesia in psychiatric patients
with tardive dyskinesia before and during treatment with alpha-
methyl-p-tyrosine (AMPT, a dopamine antagonist), biperiden (an
acetylcholine antagonist), and baclofen (a GABA agonist); and in patients
with paralysis agitans and L-dopa-induced hyperkinesia. AMPT and baclofen
had similar influences on oral dyskinesia, resulting in reduced frequency,
unchanged or slightly reduced amplitude, and increased duration of each
movement. The author concludes that: 1) reduced dopaminergic activity may
be the primary pathogenetic background for tardive dyskinesia; 2)
dopaminergic hypersensitivity and/or cholinergic hypofunction is necessary
before hyperkinesia breaks through; and 3) the neurotoxic effects of
neuroleptics may be associated with age-dependent changes in nigrostriatal
regions representing oral innervation.
