| }}Psychopathy is a psychological construct, classified by some as a personality disorder, characterized by amoral and antisocial behavior. It is a term derived from the Greek psyche (soul, breath hence mind) and pathos (to suffer), and was once used to denote any form of mental illness, often being confused with psychosis. The term is often used interchangeably with sociopathy e.g. Arthur S. Reber. Penguin Dictionary of Psychology. 2nd. ed. Harmondsworth, UK: Penguin, 1995. History Research into a group of individuals he described as psychopathic was first completed by Philippe Pinel almost 200 years ago. Pinel described patients as "insane without delirium," which he characterized as a lack of restraint and remorselessness for their actions. Pinel felt that his patients were morally neutral, reflecting his humanistic approach to mental illness.Hare, Robert D.