You want to be careful when you cross these categories of abnormal behavior: Narcisissm, Psychopathy, and Sociopathy. After all, if psychologists saw them as the same thing, they would call them the same thing. Here's how I've understood their meanings thus far:
Narcissism is a defensive behavior of denial and projection. It's extreme to the point where the lies and gaslighting are genuinely believed by the perpetrator.
Psychopathy is a lack of empathy. A sort of mirror neuron blindness that lacks the ability to see one's self in others. Has to go out of their way to consciously pretend to care about others and is putting on a show. Personally, I have a hypothesis that a psychopath has the best chance of being reasoned with as long as they can be taught the rational usefulness and self-value that comes from doing what's in the best interests of others.
Sociopathy is someone who has anger issues that are uncapped. They lack empathy like a psychopath and lack self-control like the narcissist. A sociopath harms anyone who is perceived as obstructing or threatening them, which can very well be everyone in their eyes.
These aren't textbook definitions, and to be sure, the textbook definitions are under heavy debate still. It's important to note that each of these neuroses is an event that amounts to an otherwise healthy brain lacking a complex set of inhibitions in the frontal lobe. For that reason, despite being dangerous, you cannot deny that they are human just like you. Sick in the head to the point where you would do best to avoid them more than you avoid a schizophrenic hobo. While there is no known effective treatment, people with mild or moderately functional levels of these mental illnesses have places where they can attempt to get help, regardless.
Individuals without these conditions can easily relate, most likely because we have all of the same instincts that these types of individuals act on. The most powerful method I am aware of that can help with these conditions as well as with dealing with people with these conditions is mindfulness training also known as Cognitive Behavioral Therapy. By remaining fully aware of your mental state, you can protect yourself from yourself and from others whom are being psychologically abusive.
Great post, and good luck!
Yes in this post I was specifically addressing narcissists-- the ones who actually believe their projections. That's actually the difference between gaslighting and projection. While a narcissist's behavior may seem psychopathic but it is actually the empathy and their own conscience that is the root of the problem. They develop a psychotic break between their true actions and what they perceive so as not to have to deal with their guilt and other negative feelings. Of course, the boundaries aren't clearly defined and people can display some elements of narcissism and sociopathy for instance.