Extrapyramidal side effects: a historical perspective.

A historical review of the adverse reactions to neuroleptic agents--extrapyramidal side effects--is presented. Soon after its introduction in 1952, chlorpromazine was noted to induce symptoms resembling Parkinson's disease. At first, these symptoms were thought to be related to the drug's antipsychotic effect. Later, more careful research showed that they are not directly associated with the antipsychotic activity of neuroleptic agents. More recently, extrapyramidal side effects have gained importance because they are significant factors in both the patient's acceptance of the particular drug and his or her social adjustment.