Robert Hare's Psychopathy checklist is a tool commonly used in clinical practice to assess whether an individual is a psychopath. Here are Hare’s definitions of two types of psychopath:
Selfish, callous psychopaths
Glibly, but superficially charming
Grandiose feeling of how important s/he is
Pathological liar – lies when there is no need to
Manipulates others, cunning
Lacks remorse or any feelings of guilt
Does not really feel strongly about anything
Lacks empathy
Does not accept responsibility for his/her actions
Deviant psychopaths
Easily bored, needs excitement
Feeds off other people
No realistic, long-term goals
Impulsive
Irresponsible
Lack of control over actions
Behavioural problems in childhood
Juvenile delinquency
Different types of offending
Abuses any conditions set by the courts