In “The Truth About ‘Truth Serum,’” host Hank Green of SciShow explains what happens inside the human brain when sodium pentathol aka sodium thiopental is injected and why “truth serum” doesn’t necessarily make people tell the truth.
When sodium thiopental is injected, it ends up in your brain, where it imitates one of the chemicals that your brain naturally produces when it wants to slow things down called GABA. sodium thiopental binds with your brain’s cell receptors for GABA and just sits there, this just keeps those cells from passing on signals, which, when spread out over millions of neurons, has the effect of reducing higher brain function. This can help dial down the agitated states which come from fear and anxiety, but it also makes it really hard for the brain to carry out complex thought processes, like, for example, deciding which questions to answer and making up lies.
