No, antisocial personality disorder (usually seen as psychopathy in criminology for which no paychxological diagnosis exists) is characterized by impulsive behavior, aggression, anger, lack of empathy, no regard for existing laws/rules and in inability to learn from discipline. See the Wikipedia page for more information. Lack of feeling emotions is not a defining trait in psychopathy. Lack of feeling emotions is a defining trait in schizoid personality disorder, certain flavors of depression, and dissociative or trauma based disorders.
There was an experimental procedure using trans-cranial magnetic stimulation that opened up empathy for an autistic person. (And similarly, TCMS was used experimentally to temporary induce autism in someone). So I wonder to what extent TCMS can be used for this. Though, like autism, if TCSM can reduce, it can also induce.
It's in my experience that psychopathy (or whatever we'd like to call it) is a consciousness state, and there are some people who can deliberately shift into it by choice. These are usually folks who experiment with hacking their consciousness, such as psychonauts or meditators, so I'm not necessarily talking about people who are born into it, or conditioned by circumstance into it.
The most interesting thing about consciously shifting into that state is that, once you are there, you feel zero motivation to shift out of it, even if you have the knowledge and skill to do so.
And it is not so much that there is a lack of emotion, so much as the lack of suffering when it comes to experiencing things. At that point, any morality is driven by choice, rather than by pathos.
One of the English NHS (except they're independent of the NHS) "death panels" NICE has said there's limited evidence of effectiveness of transcranial magnetic stimulation as a treatment for depression, but recommended that it's offered to some people in some situations.
