The following are symptoms of psychopathy as determined by Adolf Guggenbuhl, author of The Emptied Soul. It is important to note that not all psychopaths will demonstrate each and every symptom mentioned.

Primary Symptoms

Inability to love
Missing or absent sense of morality
Absence of psychic development (their souls seem "static")
Background depression (nihilistic, rather than romantic or "poetic" depression)
Chronic background fear (suspicious of everybody)

Secondary Symptoms

Absence of guilt feelings
Absence of any real understanding or insight (often high intelligence, but still little understanding of emotional insight)
Ability to evoke pity (women are often drawn to psychopaths and attempt to "save" them)
Charm (they succeed in bewitching those around them)
Asocial/criminal behaviour
Boredom
Social Climbing (compensates with social success; those who cannot relate through love can only relate through power)