Dyskinesias associated with tricyclic antidepressants.

Hyperkinetic movement disorders may occur as side effects of antipsychotic drugs; and a hyperdopaminergic state induced by the neuroleptic compounds is thought to be a cause of extrapyramidal disorders such as tardive dyskinesia. We have observed two cases of the dyskinetic syndrome in patients receiving tricyclic antidepressants (TCA). Because the TCA are known to have little effect on striatal dopamine but do share with the neuroleptics potent anticholinergic activity, these cases appear to support the hypothesis that the drug-induced hyperkinetic disorders are related to a diminution of CNS acetylcholine activity as well as to an increase in dopamine activity.