The Martha Mitchell effect is a process by which a belief is mistakenly diagnosed as a delusion by a psychiatrist. This is named after Martha Mitchell (the wife of John Mitchell the Attorney-General in the Nixon administration) who alleged that illegal activity was taking place in the White House. At the time her claims were thought to be signs of mental illness, and only after the Watergate scandal broke was she proved right (and hence sane).
It was first named by psychologist Brendan Maher.
