Drapetomania

Drapetomania was a supposed mental illness that American physician Samuel A. Cartwright hypothesized as the cause of black slaves running away in 1851. It has since been debunked as pseudoscience and part of scientific racism.
Etymology.
The term derives from the Greek δραπέτης ("drapetes", "a runaway [slave]") and μανία ("mania", "madness, frenzy").
Description.
In "Diseases and Peculiarities of the Negro Race", Cartwright points out that the Bible calls for a slave to obey his master, and that if he does, the slave won't want to run away.
He claimed that the disease happened when masters "made themselves too familiar with [slaves], treating them as equals".