The concept of truth serum is common in fiction as a way to get someone to tell the truth, whether they want to or not. But the prospect of a pill or injection that can actually make people more truthful has been hotly pursued in real life. Some substances, including barbiturates, have been used in real interrogations in an attempt to draw the truth out of people. But real truth serums aren’t like Wonder Woman’s lasso of truth. It’s not impossible to lie, conceal the truth, or say nothing at all, no matter what drug you’re taking. However, real truth serums may work to make people more talkative, agreeable, and less inhibited.

Two barbiturates have reputations for being “truth serums.” Even though these drugs have been used under certain conditions to interrogate people, the reliability of the information people give under the influence of these drugs is questionable at best.

But do truth serums actually work? Even if they did, should anyone use them? Learn more about barbiturates that have been used as truth serums and if they actually work.

Truth Serums

In the real world, drugs that have been investigated as truth serums include barbiturates and benzodiazepines that act as central nervous system depressants. Like alcohol, these drugs can lower your inhibitions. The theory is that someone with lowered inhibitions will be more likely to spill the truth when interrogated.

Some drugs will produce states of semi-consciousness that can remove inhibitions, relax defenses, and make people more open to suggestion. Drugs that are reputed to be “truth serums” work in this manner.

Truth serums are labels given to numerous drugs with hypnotic or sedative properties that have been used to get people to tell the truth.

The rationale is that these drugs remove resistance and mental control to consciously attempt to fabricate or mislead when a person is questioned or interrogated. Two of the most widely reputed truth serum drugs are the barbiturates Amytal Sodium (amobarbital) and Sodium Pentothal (thiopental).

How Barbiturates Work

Barbiturates work by reducing the activity in the brain and spinal cord. These medications facilitate the release of gamma-Aminobutyric acid, abbreviated as GABA, which is the main inhibitory neurotransmitter in the brain.

When this neurotransmitter is released, it results in reduced neuron activity. This produces relaxation, sedation, and feelings of well-being or even euphoria.

Legitimate medical uses for barbiturates include the following:

  • To reduce anxiety
  • To control seizures
  • To sedate, making them useful as an anesthetic
  • To numb pain


Although the use of drugs to extract information from people predated the 1943 book Narco-Analysis: A New Technique in Short-Cut Psychotherapy: A Comparison with Other Methods, and Notes on the Barbiturates, this work described the clinical use of barbiturates and other drugs to get information from people.

The case studies describe hypnotic-like states that occur in people under the influence of narcotics and barbiturates that leave them speaking freely without anxiety or regard for what they were saying. It was this book and subsequent clinical descriptions of similar data that helped to popularize the notions of real serums.

The use of drugs to extract the truth from individuals has not been upheld in the courts of the United States; however, it is occasionally used in forensic cases.

The FBI and other federal law enforcement agencies vehemently state they are opposed to the use of these methods to extract information from prisoners. The United Nations considers the use of any of these so-called truth serums to be a form of physical abuse.

Barbiturates as Truth Serums

Two barbiturates are often touted as truth serums.

Sodium Pentothal is a very short-acting barbiturate that induces sedation for only a few moments. It also decreases breathing rate, heart rate, and blood pressure, and it suppresses the activities of the central nervous system. It may be used as an anesthetic or an anticonvulsive medication. It has been used in the past as a truth serum.

Amobarbital or Amytal Sodium is an intermediate-acting barbiturate medication that can produce sedation for several hours. It acts in the same manner as Sodium Pentothal. It has also been used as a truth serum. When it is given in this manner, the resulting interview is often referred to as an “Amytal interview.” Other barbiturates could conceivably be used for narcoanalysis because they all have a similar mechanism of action and produce similar effects. However, these two barbiturates are the most notorious barbiturates that have been labeled as truth serums.

Do They Work?

There is no consistent scientific evidence that suggests that either of the barbiturates mentioned above result in people telling the truth when they are under their influence.

Certainly, people become more talkative, less inhibited, and more open to suggestion, but the evidence indicates that these individuals are not always telling the truth. Very often, they can lie consciously.

When people drink alcohol, their inhibitions are lowered; they become very talkative; and they may reveal information they usually wouldn’t reveal. However, alcohol intoxication, which has similar effects to barbiturate use, does not result in forcing people to tell the truth if they do not want to.

The same is true with barbiturates. In fact, under heavy sedation, people under the influence of barbiturates often ramble and make very inconclusive statements as opposed to being truthful and unable to confabulate. Truth serums do not force people to tell the truth, and they are not serums.

How Does Truth Serum Work?

In real life, the term “truth serum” is inaccurate to what barbiturates and similar drugs can do. They don’t force you to tell the truth. But they can make you tell the truth in the hands of a skilled interrogator. In the criminal justice world, there are interrogators that are trained to get confessions out of people they suspect committed a crime, even without the use of truth serum. They work to lower the guard of suspects so that they divulge information or confess to a crime. In some cases, all they need to do is get the person to confirm information they already suspect.

Someone that’s under the effects of a truth serum may have fewer faculties available to them to guard information. Inhibitions allow you to hold back information and make quick judgments about how you would like to present yourself to others. Barbiturates, and other depressants, lower your inhibitions and make it more likely for you to say something you wouldn’t otherwise say. Potent depressants also slow down your thinking, reaction time, and cognitive ability. Forming and communicating a believable lie takes more brainpower than telling the truth, so it may be more difficult to create lies under the effects of barbiturates. 

However, even in the hands of a skilled interrogator, there’s no guarantee that the information that comes from someone under the influence of a barbiturate will be accurate or reliable.

Other Drugs that Have been Used as Truth Serums

Some Other Widely Known Truth Serums Include the Following:

  • The drug Scopolamine (hyoscine) is used as a sedative to treat problems with the eyes, to dilate the pupils of the eyes, and to prevent motion sickness. It has a reputation as being a truth serum; however, information obtained under the influence of this drug is unreliable.
  • Opioid drugs may still be used as forms of truth serums, but they do not guarantee that people will be truthful when taking them.

LSD was used as a form of truth serum during the Cold War.

Is There any Medication or Process That can Guarantee Someone Will Tell the Truth?

“The bottom line is no drug, device (like a polygraph), or even form of torture that can guarantee that all the information extracted under its use is truthful. ”

Barbiturates may make people more talkative and less inhibited, but they cannot force people to be truthful.

Why Don’t We Use Truth Serums?

We know that there is no evidence to suggest that information obtained with truth serums will actually be reliable, and the use of injected drugs among suspects of crimes is considered physical abuse in the United States. However, there’s also the ethical dilemma of self-incrimination. It’s part of the reason, confessions that are obtained under duress aren’t allowed in courts. The right not to incriminate yourself is a part of a fair criminal justice system. While a reliable truth serum, if one was found, could potentially do some good, it may also be used to violate important rights

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