How to Write a Sociopath

When creating a sociopathic character, the disorder can be easily confused with the characteristics of a psychopath. Although they are both defined in the Diagnostic and Statistical Manual of Mental Disorders as being personality disorders, there are visible differences in the behaviour and diagnosis. Sociopaths have similar behaviours, but they are not as severe as someone with psychopathic tendencies. Both disorders are emotionless and manipulative, however, a sociopath would feel a little guilty about hurting a person they have formed a bond with, while the psychopath would not. Psychopaths are cold and calculating, and they will take time to carefully plot their revenge. Sociopaths, on the other hand, are quick to lash out and act very impulsively.
A sociopathic character in a novel can be so much more than a villain. You could make any of your characters have this personality disorder, even the protagonist if you choose. So what are the personality traits that you should remember when creating your sociopath?
They are very nervous individuals, and can lose their temper quickly and with little provocation.
They have no self-control. They will act on any impulsive thought, without any consideration for the consequences. This could manifest itself through stealing, drug taking or sex with strangers. For example, take Cathy Ames's character in East of Eden by John Steinbeck. She kills her parents,  drives one of her teachers to suicide, seduces a married man, and frames two young boys for rape.
A sociopath will not take time to consider the consequences of their actions and therefore will never learn from their mistakes. For instance, if they get caught committing a crime, they will not understand why they are being punished. They will use their warped thought process to justify their actions and blame others. A perfect example of this behaviour would be Alex in Anthony Burgess’ A Clockwork Orange.
They are complete narcissists, with an inflated ego. They will have lots of friends but no friendship will last for long. They will demand complete loyalty and obedience from their friends and if they are crossed, will cut them out of their lives and move on to the next friend.
They are unreliable, impulsive and compulsive liars. They will do anything to ensure they get their own way. They will, in fact, lie and deceive for no other reason than to see if they can get away with it. They treat life as a game, and people’s feelings are completely irrelevant to them
A sociopath does have the ability to feel emotion, but they can remove all emotion as easily as removing a coat. For example, if another character dies, they will not even bother to mimic feelings of sadness like a psychopath would. They will either react differently to everyone else or simply not react at all
A sociopath can experience love, but only on their terms. They will notice every flaw and fault in their partner and demand they are rectified.
It is important to remember that a sociopathic disorder can stem from a traumatic event in childhood so keep this in mind when creating the back-story for your character.