Original: In the USA prior to the American Civil War psychiatrists such as Samuel A. Cartwright diagnosed some slaves with drapetomania, a mental illness in which the slave possessed an irrational desire for freedom and a tendency to try to escape.
Simplified: In the USA, before the American Civil War, the psychiatrist Samuel A. Cartwright described drapetomania, an alleged disease that gave the slave an "irrational" tendency to try to escape.