Insulin Coma Therapy — Dozens of Near-Fatal Comas, Beaten by a Sleeping Pill

Summary

In 1933 the Austrian psychiatrist Manfred Sakel announced from Vienna that he could break schizophrenia by injecting patients with enough insulin to crash their blood sugar into deep coma — and reported, on uncontrolled case series with no comparison group, recovery rates of 70 to 80 percent; the distance between that claim and what a controlled trial eventually found is the whole of this case. The procedure that resulted held patients in repeated, deliberately induced hypoglycemic comas — typically a course of 20 to 60 sessions, each lasting up to an hour, terminated by glucose — across asylums in Europe and North America for two decades, and killed on the order of one to two patients in every hundred treated, with some series running higher.

Insulin coma therapy (ICT) did not survive on evidence. It survived on enthusiasm and on a flattering selection effect. As the British psychiatrist Harold Bourne argued in his 1953 Lancet paper "The Insulin Myth," ICT units selected younger, recently-ill, better-prognosis patients, lavished them with intensive nursing in dedicated wards, and then credited insulin for an improvement that the selection and the attention had largely produced. Bourne's verdict — that insulin patients were "an elite group sharing common privileges and perils," and that the coma added nothing specific — was a theoretical demolition that the field initially refused to print; the Journal of Mental Science sat on his manuscript for a year and rejected it, telling him to "get more experience."

The empirical reckoning arrived in 1957, when Brian Ackner, Arthur Harris and A.J. Oldham published in The Lancet one of the first randomized controlled trials in psychiatric history. Fifty schizophrenia patients were randomly allocated either to insulin coma or to an identical regimen in which the unconsciousness was produced by barbiturates instead — same ward, same nursing, same coma, different agent. There was no difference in outcome. Whatever the regimen achieved, insulin was not the active ingredient. Within a few years ICT had collapsed, helped over the edge by chlorpromazine, which by the late 1950s delivered comparable results without driving anyone into a coma. It was never recalled and never banned; it was simply discredited and abandoned, and it is now taught as the first major therapy retired by a randomized controlled trial — and a textbook illustration of how a selection effect can masquerade as a cure.

Timeline

1927

Sakel stumbles onto hypoglycemia as a tool

Working in Berlin and Vienna, Manfred Sakel uses small doses of insulin to calm agitated morphine-withdrawal patients, and notices that hypoglycemic episodes seem to settle them.

1933

Sakel publishes his schizophrenia results

Sakel reports inducing therapeutic comas in psychotic patients and claims recovery or marked improvement in the large majority — figures based on uncontrolled case series with no comparison group.

1935

The method crosses the Atlantic

American psychiatrist Joseph Wortis observes Sakel in Vienna and introduces insulin coma therapy to the United States, where it is rapidly taken up.

Late 1930s

ICT becomes the standard of care

Dedicated insulin units, intensively staffed, are installed in major asylums across Europe and North America; ICT becomes the leading somatic treatment for schizophrenia.

1937

Munsingwerk conference cements its prestige

International gatherings and a wave of enthusiastic literature establish ICT, alongside metrazol and the emerging shock therapies, as front-line psychiatric medicine.

1944

Sakel emigrates and is lionized

Now in New York, Sakel is celebrated as the discoverer of a frontier cure; the procedure's reputation rests on his authority and on glowing but uncontrolled reports.

1953

Bourne publishes "The Insulin Myth."

After a year-long rejection by the Journal of Mental Science, junior psychiatrist Harold Bourne argues in The Lancet that ICT's apparent success is a selection-and-attention artifact, not a specific insulin effect.

1954

Chlorpromazine reaches the wards

Marketed as Thorazine/Largactil, chlorpromazine offers a non-comatose route to calmer, more manageable psychotic patients and begins drawing resources away from the insulin units.

1957

Ackner's randomized controlled trial

Ackner, Harris and Oldham randomly allocate 50 patients to insulin-induced versus barbiturate-induced coma and find no difference, concluding insulin is not the specific therapeutic agent.

1958

Fink shows chlorpromazine matches insulin

Max Fink reports that chlorpromazine produces essentially the same results as ICT while being safer, easier to give, and suited to long-term care.

Late 1950s–early 1960s

Collapse

Insulin units close across Britain and the United States; ICT is abandoned as mainstream practice, surviving only at the fringe.

1970s–1980s

Residual use ends

Scattered use persists in Australia into the 1970s and reportedly in China into the 1980s before disappearing entirely.

A Cure Declared on Recoveries That Were Never Compared to Anything

Insulin coma therapy was born from an accident and shipped on confidence. Sakel had been using insulin to quiet morphine-withdrawal patients when he observed that hypoglycemic comas seemed to clear the minds of the agitated; by 1933 he had generalized the observation into a treatment for schizophrenia and was reporting recovery in the large majority of those he treated. His evidence was the era's standard and the era's failing: uncontrolled case series, outcomes graded by the treating physicians, no comparison group, no blinding, no agreed measure of "recovery." Because schizophrenia in young patients often remits or fluctuates on its own, and because the patients chosen for the demanding insulin regimen were disproportionately young, recently ill, and physically robust, a substantial fraction would have improved regardless of any insulin. The mechanistic story — that hypoglycemic coma somehow reset a diseased brain — was never demonstrated and is not believed now. What carried the method was the absence of any alternative in overcrowded asylums and the authority of a confident clinician publishing a dramatic result.

Industrialization of the Coma: Dedicated Units, Devoted Nursing, and a Fatal Surrogate

ICT scaled because it produced something visible. A patient injected with rising doses of insulin would sweat, twitch, convulse, and sink into coma; reversed by glucose after up to an hour and repeated 20 to 60 times over weeks, the regimen demanded a dedicated unit and intensive, around-the-clock nursing. That apparatus became the trap. The insulin wards were the best-staffed, best-resourced corners of grim institutions, and the patients selected into them were the most likely to recover anyway — so the units generated a steady supply of apparent successes that everyone attributed to insulin. This was the surrogate endpoint in its purest form: the measurable thing (a patient who emerged from the coma calmer and was discharged) was credited to the intervention, while the actual cause (selection plus attention plus natural course) went unmeasured. The cost was discounted as the price of a serious cure. Deep or prolonged comas produced irreversible brain damage and death in roughly one to two cases per hundred, with some published series higher; protracted hypoglycemia, aspiration, and cardiovascular collapse were known hazards. The deaths were logged as the unavoidable risk of a heroic therapy rather than as evidence that the therapy did nothing the barbiturate could not.

Disconfirmed by Randomization, Then Outcompeted by a Pill

The reckoning came in two stages, theory then trial. In 1953 Harold Bourne, a junior doctor, published "The Insulin Myth" in The Lancet after the Journal of Mental Science had buried the manuscript for a year and rejected it. Bourne did not yet have a trial; he had a dismantling of the existing evidence, showing that ICT's results were explained by patient selection and special treatment, not by any specific action of insulin. The profession resisted, but the logic forced the experiment. In 1957 Brian Ackner, Arthur Harris and A.J. Oldham — working across the Maudsley, Bethlem and Cane Hill hospitals — randomly allocated 50 schizophrenia patients to insulin coma or to an identical barbiturate-induced coma and found no difference between them; whatever the regimen did, insulin was not the agent. It was one of the first randomized controlled trials in psychiatry and is often cited as the first therapy rejected on randomized evidence. The verdict was sealed economically by chlorpromazine, which from the mid-1950s produced comparable results without the coma, the danger, or the dedicated unit. ICT collapsed within a few years. It was never recalled by any authority; it was discredited by a trial and abandoned by a field that had finally been shown its cure was a selection effect with a body count.

Contributing Factors

01

Uncontrolled case series mistaken for proof of cure

Sakel's foundational claim of 70-to-80-percent recovery rested on series with no comparison group, no blinding, and physician-graded outcomes, in a disease that often remits on its own. Without a control arm there was no way to separate the treatment's effect from natural course — and the whole edifice was built on that missing comparison.

02

A selection effect dressed up as efficacy

The patients chosen for the demanding insulin regimen were younger, more recently ill, and physically fitter — exactly the group most likely to improve regardless. The treatment did not cause the recoveries so much as cream them off, and then claim credit, a confound Bourne named precisely in 1953.

03

Surrogate endpoint plus intensive attention masked the truth

ICT units were the best-staffed wards in the asylum, and the lavish nursing and devoted environment — not the coma — drove much of the benefit. A measurable proxy (the discharged, calmer patient) was attributed to insulin while the real drivers went unmeasured, the classic mechanism by which an inert intervention accumulates apparent successes.

04

Institutional suppression of disconfirming evidence

When Bourne challenged the consensus, the Journal of Mental Science delayed his paper a year, rejected it, and told him to "get more experience." A field that punishes the messenger protects a false standard precisely when scrutiny is most warranted, lengthening the period of harm.

05

No internal exit ramp until a trial and a competitor forced one

ICT had no mechanism to retire itself; it took the 1957 randomized trial to disprove the specific claim and chlorpromazine to make the regimen pointless. A practice with no built-in disconfirmation test runs until external evidence and an external substitute together end it.

Aftermath

The material consequence is measured in patients held in repeated deliberate comas for an effect that did not exist, and in the roughly one-to-two-percent who died of the treatment itself across two decades and tens of thousands treated. The durable ripple is methodological. The Ackner trial is widely cited as among the first randomized controlled trials in psychiatry and as the first major therapy rejected on randomized evidence, and the ICT episode became a foundational argument for evidence-based medicine: the demonstration that sincere clinical conviction, intensive case series, and decades of consensus could all certify a treatment whose active ingredient was patient selection. Bourne, dismissed as too junior to be heard, was vindicated; his "insulin myth" is now the standard framing. Sakel, once celebrated as the discoverer of a frontier cure, is remembered as the author of an elaborately staged placebo. The hero-clinician narrative is inverted, the wonder-cure de-mythologized, and insulin coma therapy stands as the case that taught psychiatry it could not trust a recovery rate it had never compared to a control.

Lessons

Never trust a recovery rate without a comparison group. A 70-percent improvement figure means nothing until you know what happened to similar untreated patients. If a claim of cure rests on case series alone in a condition that fluctuates or remits, withhold belief until a controlled arm exists.
Interrogate who gets selected into the treatment. When an intervention is reserved for the youngest, healthiest, best-prognosis cases, its apparent success may be the selection talking, not the treatment. Audit the entry criteria before you credit the outcome.
Separate the active ingredient from the attention around it. Intensive nursing, dedicated wards, and devoted staff can drive improvement on their own. Design the comparison so the only thing that differs is the agent you are testing — as the barbiturate-coma control did — or you will credit the wrong cause.
Protect the junior who disconfirms the consensus. The evidence against ICT was suppressed for a year and waved off as inexperience. A field that punishes the messenger insulates a false standard; build channels that let disconfirming evidence reach print on its merits, not its author's rank.
Define, in advance, the trial that would prove you wrong. ICT had no internal test it could fail. Specify before deployment the controlled result that would force you to stop — and run it early — or your practice will persist until someone else finally builds the experiment you avoided.