5,000 US soldiers were made test subjects in a mind-altering drug programme. It was done to find a chemical that could disable enemies during Cold War

What if there was a chemical weapon that could defeat any enemy soldier without even killing them? During the Cold War, the US Army had tried to make this happen by exposing thousands of its own soldiers to drugs and chemical agents that could alter behaviour, trigger hallucinations and leave people unable to function normally.

These experiments where researchers studied the effects of substances ranging from LSD to nerve agents were done at Edgewood Arsenal, a classified military research facility in Maryland. The main purpose of the programme was to help the US military understand chemical warfare. But it had also left some participants with lasting health problems and led to questions whether they had been properly informed about the risks.

Why the US Army experimented with mind-altering drugs

According to 2012 report by NPR on journalist Raffi Khatchadourian's investigation for The New Yorker, the Army had tested approximately 5,000 soldiers at Edgewood Arsenal during the 1950s and 1960s.


At the first the research was done to understand how chemical agents affected the human body. But researchers later also began investigating whether these effects could be turned into a weapon that would disable enemy troops mentally rather than kill them.

Jim Ketchum, a military psychiatrist involved in the programme, defended the research as serving a larger purpose. He believed that incapacitating chemicals could offer an alternative to conventional weapons, allowing enemy combatants to be captured alive.

However, the methods used to investigate that possibility would later become a major source of controversy.

BZ could leave soldiers trapped in delirium for days

One of the chemicals studied in the research was BZ, which is a powerful incapacitating agent that can cause severe confusion and vivid hallucinations in a person.

In his interview with NPR, Khatchadourian had described how people who were under its influence could move between different perceived realities. They might see animals or miniature people that were not even there, or just believe that they were smoking or eating something when they were actually holding some unrelated object.

The effects could last for days. The Guardian reported in 2022 that BZ could leave test subjects in a state of delirium for up to three days.

Researchers also tested how the chemical might affect soldiers during military operations. In one of the experiment, three soldiers were given BZ while another just received a placebo. They were placed inside a simulated communications outpost and asked to interpret messages, respond to codes and deal with staged emergencies.

The exercise was designed to show how an incapacitating chemical could leave a military unit unable to carry out its duties.

Soldiers allegedly did not know

The programme's methods raised serious concerns about informed consent. NPR reported that soldiers signed consent forms but were not necessarily told they would be exposed to dangerous nerve agents or psychochemicals such as LSD.

Some participants were reportedly led to believe they were testing military equipment. According to The Guardian's reporting on the documentary Dr Delirium and The Edgewood Experiments, director Nick Brigden said veterans had described being threatened with court-martial if they refused to participate.

The effects could be severe even during individual tests. Khatchadourian told NPR about a soldier who received LSD without knowing what the substance was. During testing, the man struggled with mathematical problems, became paranoid and eventually punched a doctor.

Veterans continued to struggle decades later

For some participants, the consequences did not end when they left Edgewood Arsenal. A 2017 study published in History of Psychiatry examined the Army's LSD experiments between 1955 and 1967 and noted that existing reports documented frequent, serious complications.

The Guardian also reported that veterans continued to experience nightmares, flashbacks and physical or psychological problems long after the experiments. Some had been unable to explain their experiences to their families because the programme remained classified.

A class-action lawsuit sought official recognition of the experiments and relief from secrecy obligations, allowing affected veterans to seek medical support.