Drapetomania was a pseudo-scientific mental illness first proposed by U.S. physician Samual Cartwright in 1851. Cartwright wrote of the illness in his book Diseases and Pecularities of the Negro Race. Drapetomania was an illness that affected slaves and caused them to run away from their masters. Drapetes, is the Greek word for runaway slaves.
Thanks to NPR’s This American Life as the source for much of this information.