What is truth serum? It is a drug that prevents people from censoring themselves so they reveal the truth. These drugs are usually barbiturates and there is no real proof that they work.
People have searched for a drug that can help them get at the truth for thousands of years. The very first type of truth serum was wine or other strong spirits. This is where the saying “in vino veritas” (in wine there is truth) comes from. Alcohol hits the cerebral cortex, which is the part of the brain responsible for language, memory, reasoning, thought, learning, decision-making, emotion, intelligence, and personality. Alcohol slows down the cerebral cortex and the brain can’t process information as quickly or regulate itself as well. People’s inhibitions are lowered and they want to talk more. It also becomes very difficult to organize thoughts and if you are trying to lie, or keep something hidden, you need to be able to organize your thoughts. The trouble with alcohol, though, is there is no way of knowing if what the person is saying is true. So, the hunt for a drug continued.
In 1922, Robert Ernest House, a US doctor, began to believe that scopolamine was a truth serum. He used it as a mild anesthesia on pregnant women and he noticed that his patients told him things while under the drug that they normally wouldn’t. He managed to get the drug tested on two convicts in Dallas County jail and, perhaps not surprisingly, both convicts claimed that they were innocent while under the drug. They were both later acquitted. Dr. House believed that people who took the drug “cannot create a lie… and there is no power to think or reason.” Dr. House published 9 articles about the drug but there was never any definitive proof that it worked. He tended to look at the positives and ignore the negatives, such as the drug caused hallucinations, disturbed perception, and a host of other physical things.
In the 1930s, barbiturates were studied heavily. Barbiturates are sedative-hypnotic medications. They make people very drowsy and suggestible. They work in a similar way to alcohol, but much faster. Early tests showed that when people were given barbiturates they talked more freely and appeared to find it difficult to keep a secret. The theory was that it takes a lot of brainpower to tell a lie and you need to be able to concentrate. If you cannot concentrate, then it is much easier to just tell the truth. The problem was, and this is why the courts have never accepted evidence gained by interrogation using a truth serum, there was no way to tell what was true and what was fantasy. Barbiturates slow the brain down, but they also cause hallucinations and fantasies. People become very suggestible and test subjects often agreed to whatever their interrogator was saying. In several tests, subjects admitted to things that they had probably not done and they made claims that could only be fantasy. For these reasons, there is no such thing as a 100% effective truth serum. People may talk, but there is no way of trusting what they say.
There is not much evidence to go on, but a defector from the KGB said that the former Soviet Union used a drug called SP-117 to make people tell the truth. It was administered in a drink, it would make people lose control of themselves for about 15 minutes, and then they would have no recollection of anything that had happened to them during that time. However, this drug, and any other truth serum, has the same problem. By suppressing the cerebral cortex, the drug lowers people’s inhibitions and makes them talk more, but it also makes them hallucinate and fantasize. There is no way of knowing if what they say is actually true, if they are fantasizing, or if they are just saying what they think the interrogator wants to hear.
There is one way that truth serums have been effectively used. Quite often, they create a state of amnesia in the subject and they are unable to remember anything that went on during the questioning. One method used is to wait for the subject to wake up and then tell them that they confessed during the interrogation. If they were actually guilty, that might push them into talking more. However, it is rather an unethical method. And this is what I learned today.
Sources
https://www.cia.gov/static/a56eb9be08868b6e14c6ff838ae77087/Truth-Drugs-in-Interrogation.pdf
https://www.chemeurope.com/en/encyclopedia/Truth_drug.html
https://www.mcgill.ca/oss/article/drugs-history-you-asked/what-truth-serum
https://www.scientificamerican.com/article/what-is-truth-serum/
https://my.clevelandclinic.org/health/articles/23073-cerebral-cortex
https://my.clevelandclinic.org/health/treatments/23271-barbiturates