What is “Truth Serum?”

india“Truth serum” refers to various drugs that have been used in attempts to extract truthful statements from people. Wine was the basic method for extraction during ancient times, however, the first documented use of a truth serum to solve a criminal case occurred in New York in 1903. Ether, the truth-inducing drug, prompted a confession from a police officer who had murdered his wife. But the first drug ever approved as a truth inducing drug was scopolamine.

This drug was first “discovered” by Dr. Robert House, an obstetrician. When he administered scopolamine, a popular obstetric anaesthetic drug, his patients would fall into “twilight sleep,” a state in which they would automatically deliver information. After numerous experiments Dr. House concluded that he could easily force the truth from his patients through the use of scopolamine. This hypothesis was put to a test in 1922 when two convicts from a Dallas jail volunteered to be test subjects in order to prove their innocence. Under the influence of the “truth-inducing drug”’ their claims of innocence appeared genuine. In addition, after being put under the influence of scopolamine, one of the prisoner’s claimed: “After I had regained consciousness I began to realize that at times during the experiment I had a desire to answer any question that I could hear, and it seemed that when a question was asked my mind would center upon the true facts of the answer and I would speak voluntarily, without any strength of will to manufacture an answer.” The results of this experiment coupled with the prisoner’s statement verified Dr. House’s hypothesis. Furthermore, Dr. House reasoned that subjects under the influence of scopolamine would be unable to lie because the drug temporarily destroys the brain’s power of reasoning.

New substances pharmacologically similar to scopolamine were explored. Barbiturates, like sodium amytal and sodium pentothal, were used extensively during World War II for psychiatric purposes. A small dose of the drug caused the patient’s heart rate to decrease, relieved tension and anxiety. This state of complete relaxation would enable the soldiers to calmly speak of their experiences in order to lessen their trauma. Consequently, observing the advantages that could be obtained from using truth-inducing drugs, the Nazis experimented with mescaline in the Dachau concentration camp while the CIA and the U.S. Army explored alternatives such as LSD and cannabis. Their effectiveness made them an essential component in interrogations. Rumours speak of the most effective truth drug code-named SP-17, used by the KGB in interrogations and to periodically confirm their agents’ loyalty. SP-17 was extremely effective due its lack of scent and taste when added surreptitiously to a target’s beverage. Additionally, SP-17 had the ability to loosen tongues and to erase all of the victim’s memories during the time of the interrogation.

Although these drugs have never been officially proven to be completely effective, they are commonly used in various parts of the world. Truth-inducing drugs are considered unconstitutional and unethical under international law, and are classified as a form of torture. Still, in 2008 it was publicly announced that Indian police interrogators administered an unidentified drug in order to capture the gunman responsible for the Mumbai attacks, demonstrating the continual exploitation of these truth-inducing drugs.


Alexandra Pires-Ménard

2 responses to “What is “Truth Serum?””

  1. Dr. Sargon Hasso says:

    This is a very nice and succinct blog. Ethics aside, and outside LSD and cannabis substances, does any other truth drug have any side effects? If so, what are they and are there any studies to support this?

    • Alexandra Pires-Ménard says:

      The classic “truth drugs” are sodium pentothal and scopolamine. Both are controversial in terms of whether they really are effective and both can have a variety of side effects. There is extensive literature on both.
      -Joe Schwarcz

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