( CNN ) -- Back in the 1950s , Hollywood fell in love with the idea of truth serum . All manner of spies , murderers and other bad guys were given a needle containing sodium pentothal on the big screen and soon were babbling away uncontrollably as to their guilt or complicity with Red China or the Soviet Union . As recently as 2004 in `` Meet the Fockers , '' a former CIA agent played by Robert De Niro injects his would-be son-in-law , played by Ben Stiller , with the stuff to get the lowdown on his love life . Stiller 's character confesses , in a foreshadowing of Arnold Schwarzenegger 's amorous ways , to having had a child with his housekeeper , although whether he did or not is far from clear . Harry Potter knew all about truth serum . Veritaserum was used on a variety of miscreants and by evildoers . It was so powerful and feared that its use was strictly controlled by the Ministry of Magic . In reality , magical thinking is all it really is . There is no such thing as truth serum . But that news has apparently not reached Colorado . The judge in charge of the mass murder trial of James Holmes seems to think Hollywood was onto something with its fascination with truth serums . He has approved the use of a `` narcoanalytic interview '' -- such as a `` truth serum '' like sodium pentothal -- as part of a competency evaluation to determine whether Holmes was legally insane at the time he allegedly went on a rampage in a theater in Aurora , Colorado . Holmes is charged with killing 12 people and injuring many more . Sodium pentothal -- the original `` truth serum '' -- was discovered in 1936 by Ernest H. Volwiler and Donalee L. Tabern working in Chicago at Abbott Laboratories . They were trying to create an injectable drug for use in general anesthesia . Their discovery was a success and had a huge impact on surgery . Sodium pentothal is still used today to knock out patients before they are given another , longer-lasting anesthetic to keep them unconscious during surgery . Sodium pentothal made surgery far less painful . It also has an interesting side effect . People under its influence lose their inhibitions and babble on about all sorts of things , leading to some amusing moments for surgical teams . This loss of inhibition gave a few researchers hope that the drug or something like it could be used to get the truth out of people in police stations , security interrogations or trials . But outside of Hollywood , no drug passes muster as a potion capable of getting accurately at the truth . People do get uninhibited and talk more freely , but they do n't necessarily stop lying or fantasizing . They also grow more compliant , tending to agree with those asking them leading questions . There is no solid evidence that what is said under the influence of a `` truth '' drug correlates reliably with the truth . For the most part , people yammer away . If anything , they behave as if they were drunk rather than diligently affirming the sober truth . There is no drug that is going to shed trustworthy light on Holmes ' state of mind last year when , police say , he donned a gas mask as well as full body armor and grabbed a rifle , a pump-action 12-gauge shotgun and at least one .40-caliber semiautomatic pistol to launch a heinous attack . No drug can tell us what he was really thinking . In giving permission to use drugs , the judge has opened the door to a line of defense in which Holmes ' lawyers can argue that if drugged , he is being forced to testify against himself against his will . As much as some might hope for a thing such as a truth serum , none exists . Whether Holmes was bad or mad when he allegedly caused so much misery to so many people will not get resolved by a technique beloved by Hollywood movie directors but not by scientists . The opinions expressed in this commentary are solely those of Arthur Caplan .
Judge in Aurora shootings approved use of drugs for competency evaluation . Arthur Caplan : No drug can shed light on mindset of shooting suspect Holmes . He says `` truth serum , '' or sodium pentothal , is used as anesthesia for surgeries . Caplan : Only Hollywood likes the idea of `` truth serum , '' not scientists .