I can be wrong but :
A Psychopath function really differently than the Non-Psychopath.
What are their characteristics ?
> Manipulativeness : Psychopath see everything around them as pure tool,so they spend their lives learning how to perfectly feat in a place where they hide their true self to be able to do what they want without raising suspicion.
Here Vergo is the one who endorse this behavior in the way he tricks everybody, villages and Marine Base, in thinking he is a nice guy when in reality he doesn't have the slightest care for them.
On the other hand, everybody knows Akainu is a bitch and apart from the occasional manipulation ( Squardo, Ace ), he doesn't seems to hide his true-self.
> Prey and Predator relationship : Because the Psychopath thinks everybody function like he does and ( mostly ) doesn't have feeling for anybody, and maybe because he us bored, he thinks about everyone around him as a potential prey.
Both of them pursues Targets, but while Akainu focus his effort on Ace and Luffy, Vergo focus his on everybody around ( to further hide his identity ).
> Sadism : pleasure of seeing the prey having trouble. Okay... pleasure of seeing the prey suffering.
Vergo greatly shows that while Akainu doesn't seem to care much about that.
> Fear : Psychopaths feel fear but not the same as the others, from some data I collected on the net, they seems to rarely ever feel it.
Vergo didn't seem to fear anything.
Akainu was afarid multiple times : against Whitebeard, particularly against Shanks.
> Nihilism ? : Psychopath have trouble having Morals engagement and distinguishing Good from Evil. Can Psychopath hope for grand ideals and live accordingly ?
Because Akainu does fight for Morals, even if flawed ones while Vergo does seems to focus on Doflamingo pleasure...
All of that seems to indicate that while Vergo ( and Doflamingo ) seems to be pure psychopath, Akainu most likely is kind of Narcissistic with Grandeur Delires and Grand Ideals, but is able to function kind of normaly otherwise.
