Dr. Samuel Cartwright of Louisiana was an expert in the medical care of black slaves. In an 1851 book, he identified two "mental diseases" which were peculiar to slaves: Drapetomia -- the irrational and persistent desire to run away -- and Dysaethesia Aethiopica, also known as Rascality -- typified by destroying property on the plantation, being disobedient, talking back, fighting with masters, and refusing to work. Dr. Cartwright prescribed whipping as the primary cure for both mental disorders.

http://academic.udayton.edu/health/01status/mental01.htm