Note that these conditions can appear in degrees of intensity and are best formally diagnosed by a Licensed Psychologist or Psychiatrist.

Here's a quick comparison:

Narcissism

(as in Narcissistic Personality Disorder)

Main Traits: Grandiosity, a need for admiration, and a lack of empathy.
Behaviors: Constantly seeks validation, feels superior to others, and can be exploitative in relationships.

Primary Motivation:** Their self-image; they need others' admiration to feel validated.
Emotional Response:** They can experience deep shame and hurt when criticized.
Note: Narcissism is characterized by grandiosity, a need for admiration, and a lack of empathy. It can be divided into two subtypes: grandiose and vulnerable. Grandiose narcissism involves overt self-importance and entitlement, while vulnerable narcissism includes hypersensitivity and defensiveness.

Sociopathy

(as in Antisocial Personality Disorder)

Main Traits: Impulsivity, disregard for social norms and rules, manipulative tendencies.
Behaviors: May act recklessly, lie, or manipulate for personal gain. Often has difficulty forming long-term relationships.
Primary Motivation: Self-interest; focused on immediate needs without regard for others.
Emotional Response: May feel guilt selectively, typically about loved ones.

NOTE: Sociopathy is generally considered more environmentally influenced, with individuals displaying impulsive and erratic behaviors and forming attachments to specific individuals or groups.

Psychopathy

(Considered a more severe form of Antisocial Personality Disorder)

Main Traits: Lack of empathy, shallow emotions, and often charming or manipulative behavior.
Behaviors: They may mimic normal emotions to manipulate others and rarely form genuine emotional bonds.
Primary Motivation: Power/control; often uses calculated behavior to achieve personal goals.
Emotional Response: Feels little to no guilt or empathy, even towards close ones.

NOTE: Psychopathy is thought to have a more robust genetic basis and is characterized by more calculated, manipulative behaviors and a profound lack of empathy and guilt.

Key Overlaps and Differences

Overlap

All three may involve manipulative behavior, lack of empathy, and difficulty forming healthy relationships, but the differences are distinct and essential to note.

Differences

Narcissistic behavior is driven by a desire for ADMIRATION.
Sociopathic behavior is driven by SELF-INTEREST & GRANDIOSITY.
Psychopathic behavior is driven by A DESIRE FOR POWER AND CONTROL, with a more CALCULATED and often EMOTIONALLY COLD APPROACH.