You should see the documentation on it.

From what i understand, the most reliable technique discovered was to give the interrogation subject massive amounts of barbituates to the point where they would be about to pass out, then inject them with massive amounts of amphetamines. The persons body would in essence go into a state of shock, where they would have difficulty in formulating lies. However they would also have difficulty in talking at all and the procedure was extremely dangerous to the subject, yet whatever information they disclosed in this state was generally found to be truthful.