Megavitamin therapy is the name of a controversial mode of nutrient therapy that involves the ingestion of large doses of vitamins. A subcategory of orthomolecular medicine, megavitamin therapy was introduced in 1952 as a term by psychiatrists Humphrey Osmond and Abram Hoffer, who used it to describe the prescription of large doses of niacin in the treatment of schizophrenia. In fact, large doses of niacin and several other vitamins can have very serious side effects, and the medical community as a whole has not endorsed the theories of megavitamin therapy. In some rare disorders, however, certain selected megadoses of vitamins may be employed therapeutically.