Republican U.S. presidential candidate Donald Trump has been called both a "narcissist" and a "psychopath." And, while in common parlance, the two terms are often used interchangeably, there are key differences between both the disorders that one should know.

It is quite difficult to identify someone as a psychopath. They can seem quite normal and even charming but their normalcy is a mere façade. Psychopaths lack conscience and empathy thus leading them to be calculating, manipulative, impulsive and sometimes, criminal. On the other hand, psychopaths are usually gifted with incredible intelligence.

They are quite predatory in nature. They constantly seek people out to abuse for their selfish gains moving on to the next person without so much as a second thought. Psychopaths don’t fear anyone and possess a remarkable amount of confidence.

Psychopaths and narcissists have one important trait in common. They both lack empathy.

However, people suffering from Narcissistic Personality Disorder exhibit great arrogance and a constant need for attention both in their personal and professional lives. Narcissists are often described as “cocky, self-centered, manipulative, and demanding.” They believe they are entitled to special privileges and tend to hold themselves in high regard.

Although on the surface, narcissists seem to have a high self-esteem, they usually have very poor self-esteem and hence the mask. In some cases, however, it has been observed that narcissists may have high self-esteem at both levels.

Narcissists can also be quite aggressive, often acting on an impulse to gain attention. Narcissists often display emotions unlike psychopaths, indicating that while a narcissist can suffer humiliation, psychopaths don’t.