Scientific American reports that India is using “truth serum” to interrogate people associated with the recent terrorist attacks. Truth serum has a long history, and there is no evidence that it is effective, or results in getting the truth.
The idea of a “truth serum” has never been widely accepted. Although there have been waves of enthusiasm for the idea of a drug that can extract information reliably, there has been even more skepticism. Ever since the 1920s, many judges, psychiatrists, and scientists have rejected the idea that there is a drug that can get memories out intact. They have claimed, instead, that it makes people feel like talking, but it also puts them in a state of extreme suggestibility: people will pick up on cues about what questioners want to hear and repeat that back. This is one of the reasons that statements made under the influence of these drugs have never, as far as I know, been accepted in an American court.