Barbiturates aka ‘The Truth Serum’ and its Effect on the Legal World

Imagine an interrogation room and an extremely compliant confession from a suspect wearing a dazed expression readily answering questions. Does it ring a bell? Maybe it reminds you of an old crime thriller you’ve watched where the police try to extract a confession from the prime murder suspect; or a movie depicting a gangster extorting a confession from his enemies; both under the influence of a mysterious drug. The drug so administered is popularly known as the ‘truth serum’ or, in more scientific terms, Barbiturates. But how much of this is true? Does such a drug exist? And what are the legal implications of it?

Barbiturates are, in simple terms, drugs that cause depression or slow down the central nervous system. They are widely used in medicine as anesthesia, sedatives, and hypnotics. They were prescribed by doctors earlier to treat depression, anxiety, and sleeplessness but many cases of overdose led to patients dying. A lot of individuals committed suicide by purposefully using them. This led to their downfall in the market and today, doctors prescribe safer and milder medicines to treat the aforementioned problems. But in extreme cases of sleeplessness and to control seizures in case of epilepsy, they are still used.[1]

The effective way in which barbiturates acquired the notorious name of truth serums comes from the way in which it takes effect numbing the mind and lowering the defenses of the brain and spinal cord. Once administered they release gamma-Aminobutyric acid known as GABA which is the prime neurotransmitter within the brain that limits or hinders neuron activity. On the onset of relaxation owing to the drug, the individual goes into a semi-conscious state, with no strong defenses and reduced mental activity. This makes them susceptible to vulnerability, thus the drug acts as what is popularly known as a truth serum.

History of the Truth Serum

Its origin began with Dr. Robert House in 1915 when he worked in the obstetric wards. He noticed a strange change in women who were administered the drug scopolamine during childbirth. They responded to any questions put forth before them without much thought or time given to framing the answers. They spoke their mind, as though in a trance. This caused the doctor to wonder what the consequences would be if such a drug were used on suspects during interrogation. If the drug was actually as effective that it was making pregnant women forget they were pregnant in the first place, then its ramifications on murder suspects could be fathomless. By asking a question as simple as ‘Where the suspect was the night before’ his involvement in the crime could be ruled out.[2] The doctor decided to interview in the Dallas county jail, two prisoners. Under the influence of the drug, they denied the claims and accusations put on them and on trial were found not guilty. This led the doctor to conclude that under the trance created by the drug an individual loses his power to lie, he cannot seem to think or logically deduce and reason.

Scopolamine was the first-ever known truth serum popularized by Dr. Robert House. It was used in the 1920’s and 1930’s by the police department in the USA on suspects; some rare cases had the judge accepting the statements made under the influence of the drug. Another added advantage of this drug was its memory wiping after effect which rendered the subjects unable to remember the statements they had made under its influence. Many Nazis used the drug in their interrogation proceedings as well. Today, its use is limited to medicines which prevent motion sickness, the tremors of Parkinson’s disease, and, unfortunately, it is also negatively used as a date rape drug. But due to a series of side effects, the use of this drug as a truth serum was discontinued.

Pentothal or sodium thiopental was a compound invented in 1934 by Ernest H. Volwiler and Donalee L. Tabern, their primary purpose was to create another pain killer. It didn’t turn out to be successful as a pain killer so surgeons were not able to use it. Psychiatrists, however, began availing its benefits. The World Wars had caused physical as well as mental damage to the soldiers; many were unable to speak due to acute shell shock. Psychiatrists began using it in their therapy as an anti-anxiety drug to make the soldiers speak and recover as a result thereof. Both Scopolamine and Pentothal were tested out on spies who were captured. The agents and spies of the spy organizations and the CIA were also put under it so as to catch a double agent. Scopolamine was frequently used as opposed to Pentothal as it wiped away memories of the interrogation and the ones just prior to it. So, the agent or spy wouldn’t even know he had been subjected to such a drug. [3]


Someone under the effect of such drugs will simply wish to please his interrogator; the mind is relaxed in such a way that critical thinking and evaluation are lost. The imagination begins to override and the subject begins to say exactly what the interrogator wants to hear rather than what is true. It is found that when the subject is asked questions the answers of which end in a simple yes or no, it is more successful; but in cases where a more complex understanding is required the subject tends to not deliver the appropriate answer. In the case of leading questions as well, the answers tend to sway in the direction of the question when the reality is the opposite. This was identified by therapists when they discovered that patients went along with whatever was being said to them. Scientific American also put forth the observation that people under the drug would repeat back whatever cues they picked up from the questioner. People also tend to overindulge in their drugged states thus providing the interrogator with a lot of information. It is near impossible to be able to sift through all of it hoping to distinguish fact from fiction.

What Happens in a Narco-Analysis Test?

A mixing of three grams of Sodium Pentothal or Sodium Amytal which is dissolved in 3000ml of distilled water takes place. After considering a person’s sex, physical condition, age the mixture is intravenously delivered mixed with 10% dextrose, it is given to the subject over a time period of three hours in the presence and with the help of an anesthetist. In case of administration of the wrong dose, it could result in the subject entering a state of coma, or in the worst-case scenario, death.

With the slow deliverance of the drug the subject enters into a state of trance where his blood pressure becomes lower, his guards are absent and he becomes more relaxed. Investigation agencies then begin to probe by way of asking questions in the presence of doctors. Recordings in audio and video form are also done plus a written consent of the subject is taken.

Legal Implications of the Test

Article 20(3) of the Constitution of India states that a Narco-Analysis test violates the Fundamental rights guaranteed to the citizens. Protection against self-incrimination is provided under it. The same privilege is provided to the American citizens under the Fifth Amendment to the U.S. Constitution. The International Covenant on Civil and Political Rights 1966 also grants the same by Article 14 (3)(g).

In the case of Townsend v. Sain, the US Supreme Court ruled that the confessions which were given under the effects of the truth serum were inadmissible. [4] In India, lawyers are divided whether such admissions can be considered admissible in courts. The Narco-Analysis report has some bearing but its complete acceptance and reliance in a court cannot be guaranteed. In certain situations, an individual may be thinking deeply about an issue in a specific manner which he begins to feel is right, but it may not be the truth. Some believe that such a test cannot have a supporting value when it comes to evidence either.

An important principle of common law in British states is that in case a person is accused of an offence, that person shall not be forced to find any document or any object that works against him. The Fifth Amendment of the US Constitution also states that no person shall be forced to be a witness against himself in a criminal case. In the case of Dr. Rajesh Talwar and Another v. Central Bureau Investigation through its Director and Other more popularly known as the Arushi Murder Case a 14-year-old girl was murdered and found in her house. The servant Hemraj was suspected but after two days his body was found on the terrace as well. The parents were then arrested and subjected to a Narco-Analysis test, polygraph test, and brain mapping. It was pleaded that such tests not be taken as evidence and the court held that without the consent of the accused the tests cannot be taken by the authority. The Trial Court also held that admissibility of such tests was not allowed as the accused under the influence of the drug was not aware of his responses. [5]

[1] Robertson, Sally. What are Barbiturates? News-Medical. Retrieved on June 05, 2020

[2] Esther Inglis Arkell, What truths does ‘’truth serum’’ sodium pentothal actually reveal?, Gizmodo, accessed on 1st June, 2020.

[3] Esther Inglis Arkell, What truths does ‘’truth serum’’ sodium pentothal actually reveal?, Gizmodo, accessed on 1st June, 2020.

[4] Townsend v. Sain, 372 U.S. 293 (1963)

[5] Gowsia Farooq Khan, Narco analysis test: A blessing to criminal justice system, its reliability and admissibility in  light of various Judgements, International Journal of Law, accessed on 1st June, 2020.

Gursimran Kaur from KIIT School of Law

You can find her here.

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