People have been known to heal themselves through anger, too; I’ve harnessed that effect myself. And I’ve watched people die of despair, which can happen remarkably quickly.
It is very strange to see people who claim to be evidence-driven arguing that taking actions that provably alter patient outcomes (such as using placebos wisely) are “not part of medicine” or “not real medicine”, isn’t it? Great healers have written about the value of holistic mind/body treatments ever since we’ve had writing.