What truths does "truth serum" sodium pentothal actually reveal?

The famed chemical sodium pentothal, which is commonly known as truth serum, has been a mainstay of spy flicks for decades. In real life, scientists have tested it on spies, psychiatric patients, pregnant women, and suspected criminals. They all talked, but did they say something meaningful? Or was it just what the people around them wanted to hear?

Like heroin, sodium pentothal is a brand name. The drug was manufactured and trademarked by Abbott Laboratories, and its free-for-all name is sodium thiopental. It's a barbiturate, a drug that acts on the central nervous system, which it depresses to calm anxiety, induce drowsiness, eliminate pain, and sometimes entirely knock someone out. That is not why it's become world famous. Sodium pentothal made its name in detective, spy, and pulp novels, where it was famously used as a 'truth serum.' Novelists weren't making it up. Psychiatrists and police officers both swore by it in the first half of the twentieth century - but which of its powers were fact and which were fiction is still debated.

The Innocent Origin of Truth Serum


The maddening thing about Truth Serum, and the damage its wrought over the years, is that its conceptual originator, Dr Robert House, meant it to exonerate prisoners. During his time in obstetric wards around 1915, he noticed the drug administered to women during childbirth, scopolamine, had a strange effect on his patients. They spoke automatically and unthinkingly, responding to any question. His mind went to prisoners who, under interrogation, maintained claims of innocence. That's easy enough to do when jail would be uppermost in their mind, but if a barbituate could make women forget that they were having a baby, it could certainly wipe ulterior motives from a person's mind. So if asked where they were the night before, if they answered automatically, 'at home,' then they couldn't have been out robbing a bank.

What truths does "truth serum" sodium pentothal actually reveal?

The process by which sodium pentothal came to be used to obtain confessions of guilt was a circuitous one. The particular compound was invented in 1934 by Ernest H. Volwiler and Donalee L. Tabern, both of whom were trying to invent another pain killer. Although it did relax a patient, and enough of it knocked a person out, sodium pentothal didn't kill pain as much as they had hoped. It wasn't ideal for surgeons, but it came to be used by shrinks. Psychiatrists during the World Wars saw some soldiers with acute shell shock who either had great difficulty speaking or were unable to speak at all. Earlier barbiturates were used during therapy, but since it did not completely incapacitate a patient as much as they did, sodium pentothal was an ideal drug to be used in programs as an anti-anxiety drug which allowed the soldiers to speak and to eventually recover from their experience - provided addiction was kept at bay and their psychiatrist was conscientious. These programs, during which the drug was injected and the scientist asked questions, were surprisingly progressive, in that the drugs wore off and allowed the soldier to go back out into the community, instead of taking long stays in a psychiatric facility. The idea was to remove inhibitions, including fear of reprisal, and let the soldier talk, then let him recover and go back out, fully integrated into the community. It is still, at times, administered in the UK for the treatment of phobias.

The Twisted Side of Truth

These psychiatrists consulted at police stations, and it wasn't long before people began making the connection between removing a soldier's fear of past events and removing a criminal's fear of getting caught was made. Truth serum has had no real history in the courts. Courts generally haven't been kind to barbiturate confessions. They have however, recognized confessions when the fact that barbiturates had been administered to the suspect went quietly unmentioned. Throughout the first half of the twentieth century, scandals popped up when investigating officials found that police had administered such drugs to suspects. Even if the person never mentioned anything of substance while under the influence, they generally woke up with no memory of anything that happened. A signed confession waved in their face might induce an amnesic suspect to talk, or to incriminate themselves as the only way to save themselves from a harsh sentence.

What truths does "truth serum" sodium pentothal actually reveal?

Spies at least tested out the benefits of sodium pentothal, sodium amytal, and even good old scopolamine, was tested by the CIA and other spy organizations. They used it on spies they captured, and on their own agents, hoping to catch a double agent in the ranks. Scopolamine was the most frequently used, because it not only wiped out memory during the session, but just previous to it as well, so a person wouldn't know the situation that led up to their memory loss. Just after September 11th, people began talking about administering it to suspected terrorists in custody.

While police officers and spies were attempting to get confessions from criminals, psychiatrists attempted to convince their patients that they had been the victims of crimes. Sodium pentothal use had slowly mutated over the years. While under the influence, soldiers would relate extraordinary stories of their time in the war, and of the time before that. Many doctors were shocked at the abuse that some soldiers had suffered as children. Doctors began to ask about it, and even expect it, and since sodium pentothal left a patient confused and semi-coherent, it led to misunderstandings. One of the most famous of these was the infamous Sybil multiple personality case, which sprung from a young woman under the influence of barbiturates telling her psychiatrists about a tonsillectomy that she had undergone as a child. The incident seemed like an assault to Cornelia Wilbur, her doctor. The doctor probed for more details, which were supplied by Sybil, and worked up a case history that changed psychiatry.

But Does It Work?

Well, it might. If someone is dead set against telling your their secrets it might make them so disoriented that they'll spill something. It's just that, to make it at all effective, you have to positively know what you're looking for already, because if they tell you that, they'll generally tell you a lot of other things as well. And you'll have to work on your tone, because someone under the influence of any of the 'truth drugs' will most likely tell you what you want to hear. The drugs make people a little more obliging, but mostly they suppress the parts of the brain that have to kick into gear if a person is to assess what's wrong with a question, articulate it, and assert themselves to their questioner. It's easier just to let their imagination go with the flow and tell the questioner exactly what they want to hear.

What truths does "truth serum" sodium pentothal actually reveal?

That is not a problem if all the questioner wants is a confession, right or wrong. If they want information, though, sorting out a person being honest, being imaginative, misunderstanding the question, and outright lying because it's easier, is tough to do. One of the reasons Multiple Personality Disorder was nailed down as only being cause by severe child abuse is Doctor Wilbur insisting that that was the only cause. Earlier patients mentioned mildly traumatic events in childhood but not necessarily direct abuse, nor was that trauma the only cause of the split in personality. Wilbur then founded an organization which trained therapists to use drugs and hypnosis and probe for childhood abuse. After many leading questions, patients would finally go along with what their therapists were saying, the therapist would declare that a memory had finally be recovered, and the cause of the illness would be reinforced. Recovered memory abuse would range from Sybil's false memory of being flown to (occupied) Holland during World War II to help an English officer smuggle out his wife, all while in the persona of a twelve-year-old, to fantastic stories of Satanic cults sacrificing humans inside regular towns. When cases against parents started falling through, and lawsuits started piling up, truth drugs fell from favor fast. Meanwhile, when the Supreme Court declared that confessions under the influence were coerced, which was unconstitutional, and the easy confessions turned into a lot of freed prisoners, with occasional scrambles to collect old evidence.

In the end, sodium pentothal proved useless not because no one could get information, but because everyone could get too much. It gave questioners information in endless streams that were near-impossible to sort into fact and fiction. It dangled exactly the reply people wanted in front of them, but made anyone who was informed about the drug question if it was only there because they wanted it. It can't offer any certainty that information gotten out of a person was anything more than fantasy. And since certainty is what 'truth serum' is supposed to be all about, then it definitively fails.

Top Image: Armin Kübelbeck

Second Image: SkewsMe

Sybil Image: WRVO

Needle Image: Armin Kübelbeck

Via Scientific American, CHM, BBC, and Damn Interesting.