Your question is similar to a thread from a few days ago:
[url]http://www.ar15.com/forums/topic.html?b=1&f=5&t=218547[/url]
This is what I answered:
-----------------------------------------------
Barbiturates, and many CNS depressants in general, will initially cause [b]disinhibition[/b] before causing the person to fall asleep/become comatose. Alcohol is another good example of this.
People who are under a lot of stress will frequently develop medical symptoms that have no physical basis. This is called a conversion reaction (first well-described by Freud)--they convert [b]psychological stress[/b] into a [b]physical symptom[/b]. This is a [b]sub-conscious[/b] process. If they are intentially doing it for monetary gain (disability claim), then it is called malingering.
In residency, we used to admit people who would, for instance, claim not to be able to move their legs. After all tests were negative, we would sometimes perform a sodium pentothal 'interview'. We would set up an IV and slowly inject the drug, stopping periodically and 'encouraging' them to move their legs. We would videotape it and have a family member present as a 'witness'. A signed, informed consent to do the procedure was also obtained from the patient. The patient would then magically start moving their legs.
The drug will disinhibit someone to the point that they may tell you what you want to know. They will have amnesia for the procedure and it is painless. In the right hands, there is a very low risk of causing any injury.
If the answers you are looking for are verifiable, ie. location of money or WMD, then it can be an excellent interrogation technique.