Interestingly, a placebo also works when the recipient knows it is a placebo. Therefore, "pills" for nausea or insomnia may well help, even if you made the miraculous capsules yourself in the kitchen ten minutes ago.
en.wikipedia.org (section Interesting facts) geektimes.ru www.psychologies.ru
It all depends on your suggestibility. It is quite possible to convince yourself that they are acting and fall asleep. Some people manage to inspire themselves with headaches and insomnia. It may also be the other way around, that you take a sleeping pill, thinking that it is a placebo and imagine you will not fall asleep. Whether it is possible to inspire oneself with death, pregnancy or superpowers is a question.