" Methylene blue was a kind of home run that disappeared from psychiatric use not because it was ineffective or barbaric but because, according to British psychopharmacologist David Healy, “patents had been obtained on newer agents and no drug company would market an old drug even if it worked.” In the case of methylene blue, then, “there were competing therapies or interest groups likely to make more money out of other therapies than they would from methylene blue.” In the 1970s, methylene blue reemerged as a means of treating manic depression, for which it was highly effective, but ultimately corporate profit-seeking interests rather than therapeutic outcomes won the day. "

― Lauren Slater , Blue Dreams: The Science and the Story of the Drugs that Changed Our Minds