When having a hard day, people think drugs wear off faster

Iowa State

Drugs interact with our brain in profound ways, even when their target is a completely different part of the body. The brain is essential for making sure that placebos work, as well as generating the nocebo effect, where harmful side effects appear in cases where no drug has been taken. It's probably not much of a reach to expect that the brain will also influence how long people think the effects of a drug will last.

The unexpected twist is that researchers have now shown that we think drugs will wear off faster when we're working harder. And, given the chance to self-medicate, we'll keep popping pills as long as things are stressful or difficult.

Researchers at the Baruch College and the London School of Economics were inspired in part by a question someone asked on a medical advice site as to whether the exertion experienced during yoga might reduce the effectiveness of botox injections. The researchers suspected that this sort of reasoning might derive from daily experience—after all, people see that driving faster uses up gas more quickly. So they decided to test the theory.