Most people know how truth serum is supposed to work: bad guy is lying, good guy forces him to drink truth serum, and bad guy spills the evil plot to take over Nakatomi Plaza. While words like amobarbital and sodium pentothal sound like scary compounds that could induce the truth, they are nothing more barbiturates, a fancy class of drugs very similar to alcohol. For the Fratellis and bad guys everywhere, there is little to fear about truth serum.
Numerous studies have shown that people can lie when given truth serum. Those studies falsify the claim that truth serum produces truthful statements. Some evidence points to truth serum simply increasing how talkative someone is, but creates the problem of decifering facts from fiction. The 'truth' is that truth serum doesn't enchance memory in any way. Truth serum is as reliable as asking 'Zoltar Speaks' to reveal the truth.
The studies make sense, given the fact that barbiturates are very similar to alcohol. Even in large quantites, alcohol rarely reveals secrets more important than 'Harry thinks Sally is attractive' or 'I am your father'. We are just as likely to lie and tell the truth under both circumstances.
In my opinion, a more effect way to get the truth out of people is to give them Saturday detention for eight hours and fifty four minutes.
Ref: pg 421, 191.