Insulin Shock Therapy (IST), also known as Insulin Coma Therapy (ICT), was a biological psychiatric treatment used extensively from the 1930s through the 1950s. Introduced by Polish-Austrian psychiatrist Manfred Sakel in the late 1920s, it was primarily used to treat schizophrenia. The procedure involved intentionally inducing a deep, life-threatening coma in patients through massive insulin injections. IST was abandoned due to serious concerns over patient safety and a lack of proven effectiveness.
The Mechanism of Induced Coma
The core procedure of Insulin Shock Therapy centered on the deliberate manipulation of the patient’s blood sugar levels to an extremely low point, a state called profound hypoglycemia. Patients received daily injections of progressively higher doses of insulin, which rapidly depleted the brain’s primary energy source, glucose, leading to a loss of consciousness. This process would induce a deep coma, which could last for an hour or more, sometimes preceded by symptoms like profuse sweating, tremors, and seizures. The treatment was terminated by the rapid administration of a concentrated glucose solution, often intravenously. Practitioners believed that this extreme physiological stress—the intense “shock” of hypoglycemia—could “jolt” the patient’s brain out of their psychotic state, acting as a corrective measure for presumed biological dysfunction.
High Rates of Severe Complications
The primary reason for the abandonment of Insulin Shock Therapy was the high rate of severe, life-threatening complications. The intentional induction of profound hypoglycemia placed immense stress on the patient’s physiological system. The most significant danger was irreversible brain damage, which occurs when the brain is deprived of glucose for too long. The mortality rate associated with the procedure was high for a psychiatric treatment, estimated between 0.5% and nearly 5% of all treated patients. Patients frequently suffered prolonged or irreversible comas, where the medical team could not successfully resuscitate them, and severe hypoglycemia also commonly triggered grand mal seizures, which increased the risk of neurological injury. Beyond neurological risks, the treatment was associated with serious cardiovascular complications, including shock and collapse. These inherent physical dangers made the procedure ethically and medically indefensible.
Failure to Demonstrate Clinical Efficacy
Despite its widespread adoption, rigorous post-war clinical studies ultimately failed to demonstrate any significant long-term benefit for patients treated with Insulin Shock Therapy. Early proponents claimed high success rates, but these were based on uncontrolled, observational studies lacking modern scientific controls. The scientific consensus began to shift in the 1950s as more objective evidence emerged. Comparative studies showed that the outcomes for patients receiving ICT were often no better than those receiving less dangerous or sham treatments. For example, some trials found no statistical difference between the effects of insulin-induced coma and those of a coma induced by barbiturate drugs. This suggested that any temporary benefit was related to the non-specific effects of being in a coma state. Furthermore, long-term follow-up data was discouraging, indicating that many patients initially considered “improved” experienced high rates of relapse. This lack of therapeutic superiority, combined with the extreme risks, led the scientific community to condemn the practice as ineffective and unnecessarily dangerous.
Transition to Safer Psychiatric Treatments
The final decline of Insulin Shock Therapy was cemented by the introduction of safer and more effective therapeutic alternatives in the mid-1950s. The most significant development was the arrival of the first generation of psychotropic medications, particularly the antipsychotic drug chlorpromazine. These new medications offered a non-invasive, manageable way to address the severe symptoms of conditions like schizophrenia. Studies comparing ICT to chlorpromazine found that the drug offered comparable symptom relief without the risk of coma, brain damage, or death. The new pharmacological treatments were easier to administer, required less specialized staff, and were better suited for long-term care, making the cumbersome and labor-intensive ICT procedure obsolete. Major psychiatric organizations progressively withdrew their support throughout the 1950s and 1960s, leading to the near-total abandonment of Insulin Shock Therapy.