Neurology & Psychiatry · 1952
Chlorpromazine in psychosis (Delay & Deniker)
In the early 1950s, the acute psychiatric wards of European hospitals had limited options beyond physical restraint, barbiturate sedation, and electroconvulsive therapy. Patients in manic or psychotic states were frequently kept under heavy sedation or in isolation, and the sedation itself prevented any assessment of whether the underlying psychosis was improving. The standard pharmacological tools blunted behavior broadly without touching hallucinations or delusions. Henri Laborit, a military surgeon in Paris, noticed in 1951 that a new antihistamine compound, chlorpromazine, produced a state of unusual calm and indifference to pain in surgical patients awaiting procedures, without rendering them unconscious. He described it as producing a kind of detachment and urged colleagues in psychiatry to investigate it.
Paul Charpentier had synthesized chlorpromazine at Rhone-Poulenc in December 1950 as part of a systematic effort to produce better antihistamines with sedative properties. Laborit's informal report reached Jean Delay and Pierre Deniker at the Sainte-Anne Hospital in Paris, where Delay directed the department of mental illness and encephalopathy. Beginning in January 1952, they administered chlorpromazine to acutely psychotic patients, starting with a 57-year-old man with manic agitation who had not responded to other treatments. His condition improved within days. Delay and Deniker published their first series in the Annales Medico-Psychologiques in May 1952, reporting reductions in agitation, hallucinations, and delusional thinking without the stupor that barbiturates produced.
The distinction mattered clinically. Prior sedatives suppressed behavior; chlorpromazine appeared to reduce the psychosis itself while leaving the patient awake and communicable. Delay and Deniker called the effect neuroleptic, meaning the drug gripped or seized the nervous system in a specific rather than global way. They identified what would later be recognized as dopamine blockade, though the receptor pharmacology was not worked out until the 1960s and 1970s.
Smith Kline and French licensed chlorpromazine and introduced it in the United States as Thorazine in 1954, following rapid adoption in Canada and Europe. The drug's arrival coincided with a period of administrative and political pressure on state psychiatric institutions, and the two forces together produced a measurable demographic shift. The number of patients in U.S. state psychiatric hospitals peaked at approximately 560,000 in 1955 and declined to under 200,000 by the mid-1970s. Deinstitutionalization policy, inadequate outpatient infrastructure, and chlorpromazine all contributed, in proportions that historians of psychiatry continue to debate.
Chlorpromazine also stimulated the search for its mechanism, which eventually led to the dopamine hypothesis of schizophrenia and to a generation of antipsychotic drug development. Arvid Carlsson, whose work on dopamine neurotransmission was foundational to understanding how neuroleptics work, received the Nobel Prize in Physiology or Medicine in 2000. Chlorpromazine itself is still on the World Health Organization essential medicines list, though second-generation antipsychotics with different receptor profiles and side-effect spectra have largely replaced it in high-income settings.
Key People
- Jean Delay — French psychiatrist who led the first systematic clinical trials of chlorpromazine
- Pierre Deniker — Psychiatrist who co-conducted the Paris trials and defined the drug's indications
- Henri Laborit — Surgeon who first observed chlorpromazine's unusual calming properties
- Paul Charpentier — Chemist at Rhone-Poulenc who synthesized chlorpromazine in 1950
- Arvid Carlsson — Pharmacologist whose dopamine research explained chlorpromazine's mechanism of action
Delay J, Deniker P, Harl JM. Ann Med Psychol (Paris). 1952;110(2):112-117.
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