In sport competitions, this is particularly important because, according to the Prohibited Drugs List 2007 of the WADA, drugs can be divided into those that are prohibited at all times and those that are prohibited only during competition. For example, morphine is considered to be an illegal drug only during competition, whereas its use out of competition is legal. Therefore, one could conceive a precompetition conditioning with morphine and then its replacement with a placebo on the day of competition.
On the basis of these considerations, in the present study we simulated a sport competition, whereby four teams of 10 subjects each had to compete with each other in a competition of pain endurance. The four teams underwent different training procedures, with and without morphine, and then their performance on the day of competition was assessed. The possibility of evoking morphine-like, opioid-mediated, placebo responses during sport competitions highlights the impact of the neurobiological approach to the placebo effect on an important aspect of our society.