Drapetomania was a proposed mental illness that, in 1851, American physician Samuel A. Cartwright hypothesized as the cause of enslaved Africans fleeing captivity.^{[1]: 41 [2]} This hypothesis was based on the belief that slavery was such an improvement upon the lives of slaves that only those suffering from some form of mental illness would wish to escape.^[3][4]

Cartwright specifically cited the tendency of slaves to flee the plantations that held them. Since slaves happy with their condition would not want to leave, he inferred that such people had to be sick, impervious to the natural order of things. He published an article about black slaves' illnesses and idiosyncrasies in De Bow's Review.^[5][6] Contemporarily reprinted in the South, Cartwright's article was widely mocked and satirized in the northern United States. The concept has since been debunked as pseudoscience^[7]: 2 and shown to be part of the edifice of scientific racism.^[8]

The term derives from the Greek δραπέτης (drapetēs, 'a runaway [slave]') and μανία (mania, 'madness, frenzy').^[9]

As late as 1914, the third edition of Thomas Lathrop Stedman's Practical Medical Dictionary included an entry for drapetomania, defined as "vagabondage, dromomania; an uncontrollable or insane impulsion to wander."^[10]

Cartwright described the disorder—which, he said, was "unknown to our medical authorities, although its diagnostic symptom, the absconding from service, is well known to our planters and overseers"^[9]—in a paper delivered before the Medical Association of Louisiana^[7]: 291 that was widely reprinted.

He stated that the malady was a consequence of masters who "made themselves too familiar with [slaves], treating them as equals".^[11]

If treated kindly, well fed and clothed, with fuel enough to keep a small fire burning all night—separated into families, each family having its own house—not permitted to run about at night to visit their neighbors, to receive visits or use intoxicating liquors, and not overworked or exposed too much to the weather, they are very easily governed—more so than any other people in the world. If any one or more of them, at any time, are inclined to raise their heads to a level with their master or overseer, humanity and their own good requires that they should be punished until they fall into that submissive state which was intended for them to occupy. They have only to be kept in that state, and treated like children to prevent and cure them from running away.^[12]