The popular saying that drunks and children never lie alludes to the disinhibiting capacity of alcohol . According to the Roman historian Tacitus , the Germanic peoples used to drink abundantly before holding their councils, so that drunkenness would protect them from lies before making important decisions.
This belief is well reflected in the maxim in vino veritas, in aqua sanitas , by the writer, also Roman, Pliny the Elder , which we can translate as “in wine is truth, in water is health”.
Since ancient times, we have wondered how to know if someone is telling us the truth . To this end, we have designed strategies of all kinds. From ancient torture to modern polygraph machines and truth drugs .
In truth, police interrogations would be much simpler if we had a substance capable of altering the psyche of detainees to obtain the information that they voluntarily did not want to provide us. American physician Robert House believed he had found the solution in the early 1920s .
Robert Ernest House was an obstetrician. In his consultation, caring for women during childbirth, he realized that the effects of scopolamine -used at the time as an analgesic to give birth- did not prevent patients from responding with enough precision and apparent sincerity to his questions, to despite being in a state of conscious sedation , which was then called twilight sleep. With his willpower weakened by the influence of the drug, it might be harder to lie, House thought.
The year was 1916 , and chance opened the door to experiments in police interrogation . If innocent convictions could be avoided that way, it was worth a try.
Scopolamine is an alkaloid present in several poisonous plants. But its sedative action leads, as the dose is increased, unpleasant side effects: disorientation, mental confusion, slurred speech and delusions. Therefore, it was discarded as a truth serum.
The next candidate, mescaline , a hallucinogen naturally present in various types of cacti, gave a similar result. Countries like the USA, the UK and Germany experimented with it during World War II, but the testimonies obtained under the effects of mescaline did not have the expected quality, becoming contradictory.
In the 1950s and 1960s , the secret US Central Intelligence Agency ( CIA ) projects MK Ultra and MK Delta focused on the use of the hallucinogen LSD (lysergic acid diethylamide, commonly called acid) and the stimulant MDMA (methylenedioxymethamphetamine) as drugs to manipulate behavior and force confessions.
The first reports from military researchers on LSD seemed promising, as subjects succumbed to an initial euphoria and began to talk. But then the same problems appeared as with mescaline and scopolamine: extreme hallucinations , bouts of madness, confusion , and altered thinking.
Sodium thiopental, an effective truth serum?
The hallucinogenic experiences of the suspects drugged with LSD and mescaline , so charged with anxiety, prevented the interrogations from being carried out. The truth serum would have to be somewhere else, in a substance that didn’t cloud individuals’ cognition so much, produce hallucinations or trigger their anxiety.
The solution was sought in barbiturates , central nervous system sedatives that can work as hypnotics. Among them, one substance stood out: sodium thiopental . Better known as amytal or sodium pentothal, it is a fast-acting and short-acting anesthetic that forms part, along with pancuronium bromide and potassium chloride, of the lethal injection used in executions for the death penalty.
The researchers found that sodium thiopental relaxed individuals and produced disinhibition , causing the interviewees to express what was going through their heads, without filters.
But the effects of the drug brought a big problem: the interrogated people mixed truth with fantasy , and showed a decrease in cognitive reaction speed, making it difficult for them to concentrate. In addition, they were more suggestible to questions and tended to think with little clarity and generate false memories, which meant that the information extracted was of doubtful validity .
The alcohol of the Germans and the Romans did something similar, loosen the tongue. But rampant verbiage is no guarantee of truth. Which is why the truth drug failed in its purpose.
The CIA itself had to conclude, in a 1961 report (published in 1993) that there is no such magical concoction popularly known as truth serum , so famous in movies and literature. Not even the best candidates, the barbiturates, achieve their goal. By depressing the central nervous system and impairing cognition, they can make people more vulnerable and reduce their psychological defense mechanisms, but, the report says, “even under the best of conditions, they will lead to an outcome tainted by deception, fantasy, slurred speech, etc.”
Apart from its scientific invalidity and the almost complete absence of controlled experimental studies, the use of drugs for interrogation purposes is currently considered torture in several countries, and conflicts with the right not to testify against oneself, which is included in some legislations.
So the question we asked ourselves at the beginning must be answered with a yes and a no. Yes, there are substances that have been used (mostly under cover of illegal and secret government programs) in order to extract information against the will of suspects. Institutions in various countries have acknowledged having used drugs in this context. But no, no drug has been shown to be effective in that regard.
The truth serum has a lot of lies in it.
References:
Bimmerle, G. 1993. Truth Drugs in Interrogation. CIA Historical Review Program.
House, R. E. 1931. The use of scopolamine in criminology. Am. J. PoliceSci., 2, 328.
McCoy, A. W. 2007. Science in Dachaus shadow: HEBB, Beecher, and the development of CIA psychological torture and modern medical ethics. Journal of the History of the Behavioral Sciences, 43(4), 401.
Passie, T. et al. 2018. MDA, MDMA, and other “mescaline‐like” substances in the US military’s search for a truth drug (1940s to 1960s). Drug testing and analysis, 10(1), 72-80.
Winter, A. 2005. The making of ” truth serum”. Bulletin of the History of Medicine, 500-533.
