Another overused word. To my understanding, brainwashing is a term that first came into use during the Korean War, when captive American soldiers denounced their government and its intentions.

The process is not as casual as the current use of the term would lead one to believe, but involved deprivation (for example, locking the prisoner in a completely dark room for days, denial of food, water, and sanitary facilities) in addition to psychological techniques based on Pavlov's work on the conditioned response.