Question: What is a placebo?

Jack Heal answered on 19 Mar 2013:

The placebo effect is amazing. A placebo is, as Yalda said, a fake drug. Often it’s a sugar pill. So it’s something that looks exactly like the real drug, and the patient believes it to be the real drug, but actually it does nothing at all to your body.

The placebo effect is when a patient has taken a placebo (thinking it’s a real drug) and then feels the effect of the drug, because that’s what they think they’ve taken! This is pretty weird straight away – suddenly, someone has been “tricked” into being better, rather than been properly treated.
But it goes further. There have been studies shown that two placebo pills work better than one (!!!!). More “drug” = more effect. The colour of the pill matters too – blue pills are better anti-depressants (we see them as calming, maybe?) than red pills! This is nuts! If you get an fake injection instead of a fake pill, the effect is stronger. Because we perceive the injection to be a more dramatic intervention, we feel the effects of the fake treatment more severely.
Placebos are used in trials as a ‘control’, so that we know if the drug being tested is better than nothing. In other words, is the drug having the effect, or is the act of giving someone a drug and telling them it’ll help having the effect?
Placebos can even have side-effects like normal drugs. If you tell patients that the “drug” (placebo) will make them vomit, then they may well start vomiting! You can tell them a drug will make them ill and, guess what, it might well do so. This is called the “nocebo effect”.

It’s absolutely nuts. As Yalda said, it certainly makes you think about the role of the brain in these kind of things.

I read a book called “Bad Science” which had a whole section on the placebo effect. It really blew my mind – I’d definitely recommend it if you get the chance to read it!