Extrapyramidal Side Effects

   (EPS)

   "Extrapyramidal" means the tracts of the spinal cord involved in the involuntary movement of muscles: the pyramidal tract is for voluntary movement; "iatrogenic" means medically caused. Iatrogenic symptoms such as shuffling gait; tremor of the hands, tongue and facial muscles; and "oculogyric crises" (involuntary rolling upward of the eyes) caused by the effect of antipsychotic medication on these extrapyramidal tracts are referred to as extrapyramidal side effects, or EPS; they are also sometimes called extrapyramidal "signs," "symptoms," or "syndrome."

   The term "extrapyramidal motor reactions" goes back to British neurologist Samuel Alexander Kinnier Wilson’s (1874–1937) article on "the old motor system and the new" in the Archives of Neurology and Psychiatry in 1924. Yet, the first clinical observations of EPS in connection with antipsychotic drugs date from the mid-1950s. In 1954, Hans Steck (1891–1980), professor of psychiatry at the university clinic at Céry-Lausanne in Switzerland, called attention in the Annales médico-psychologiques to an "extrapyramidal syndrome" in patients on chlorpromazine and reserpine. As well, in 1954 Hans-Joachim Haase (1922–), then a staff psychiatrist at the mental hospital in Oberwil-Zug, also in Switzerland, reported in the Nervenarzt that chlorpromazine patients were developing a "Parkinsonian" syndrome. (See Parkinsonism: Neuroleptic Induced; Tardive Dyskinesia.)