This interview, as part of the court’s efforts to determine whether or not Holmes was legally insane at the time of the mass shooting, will use a “truth serum,” such as sodium pentothal. (An article in Slate defines a “narcoanalytic interview” as an interview between a psychiatrist and a patient–in this case, Holmes–during which the patient is given a drug such as sodium amobarbital. The patient is then questioned about the event by the psychiatrist after showing one or more symptoms of the drug’s effects.)
This article opines that the use of a truth serum is “magical thinking,” an opinion with which we concur. “Truth serums,” the stuff of Harry Potter movies and other fantastical works, have long been a dream of scientists and law enforcement. The original “truth serum,” discovered in 1936, is still used during surgery to keep patients unconscious. The side effect of this drug encouraged many to think of it as a “truth serum”: it made patients suffer a loss of inhibitions, meaning they would jabber on.
But does a lack of inhibition mean that someone is necessarily telling the truth? The answer is no. Though people on the drug do talk more uninhibitedly, they may not stop lying. In addition, they are apt to “grow more compliant, tending to agree with those asking them leading questions.” Because of this compliant tendency, a “truth serum” used to find the truth could have the opposite effect.
The use of actual, reliable “truth serums” would be an immense benefit to law enforcement during interrogation. Unfortunately, they do not exist. There is a complete lack of evidence that people under the influence of a “truth serum” reliably communicate the truth. As a result, it is preposterous to allow this pseudo-science as sound evidence in a court of law.
The author of the article notes that the judge’s decision may pave the way for Holmes’ defense lawyers to argue that his Fifth Amendment rights against self-incrimination are being violated if he (Holmes) is questioned while drugged.