Temporary insanity in an individual or group resulting in a
violent or murderous reaction, induced by extreme conditions, stress or emotions (usually warfare). Can occur in even the most peaceable of peoples.
By its nature the term hints at man's (supposed and probably correct) innate predisposition towards violence.
An example is included here of an account by anthropologist Robert K Dentan of The Semia tribesmen of Malaya, a notably peaceful people who are careful to train their children in habits of non violence. Some of the Semia men were recruited by the British government in a campaign against communist guerrillas in the early 1950s. Dentan says:
"Communist terrorists had killed the kinsmen of some of the Semia counterinsurgency troops. Taken out of their nonviolent society and ordered to kill, they seemed to have been swept up in some sort of insanity which they call 'blood drunkenness'. A typical veteran's story runs like this. "We killed, killed, killed. The Malays would stop and go through peoples pockets and take their watches and money. We did not think of watches and money. We thought only of killing. Wah, truly we were drunk with blood". One man even told how he had drunk the blood of a man he had killed."