This is straight from a Wikipedia article —

The Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM IV-TR), defines antisocial personality disorder (in Axis II Cluster B) as:

A) There is a pervasive pattern of disregard for and violation of the rights of others occurring since age 15 years, as indicated by three or more of the following:

  1. failure to conform to social norms with respect to lawful behaviors as indicated by repeatedly performing acts that are grounds for arrest;
  2. deception, as indicated by repeatedly lying, use of aliases, or conning others for personal profit or pleasure;
  3. impulsiveness or failure to plan ahead;
  4. irritability and aggressiveness, as indicated by repeated physical fights or assaults;
  5. reckless disregard for safety of self or others;
  6. consistent irresponsibility, as indicated by repeated failure to sustain consistent work behavior or honor financial obligations;
  7. lack of remorse, as indicated by being indifferent to or rationalizing having hurt, mistreated, or stolen from another;
What do you think of those 1-7 above? Does Loki have at least three? By the Avengers timeframe I’d give him a big yeppers on 1, 2, 4, 5, and 7. I think probably a few of his actions in Thor were impulsive, but I’d say in the bigger picture he’s rather the opposite, a planner and long-term thinker and strategist. That’s my take, anyway.
Luckily for Loki,

There has been some research on the treatment of ASPD that showed positive results for therapeutic interventions.