What is the purpose of a sociopath?

[jafar]

Would a person who plans to incarnate on Earth as a sociopath be an individual on the service to self path? And if so, what type of advice would the inner plane guides or higher self give to this entity during the preincarnative experience? Would they tell the person to continue on this service to self path?

Although a service to self wanderer is rare as Ra states, could these sociopaths also be STS wanderers?

Well a 'person' can only be defined once it has been incarnated.
The one who do the 'incarnating' is the 'higher self' of that 'person'.

Higher self have many personas, each took their unique path.
Some STS some others STO and anything in between.

As for the 'purpose'..

One of the best way to model this and referenceable by everyone is using the metaphor of novel writer.

Let's take Lord Of The Rings (LOTR) written by Tolkien.
Within the LOTR there are many personas, Frodo the hobbits, Legolas the elf, Gandalf the white wizard, Saruman the once white but then turn black wizard, Sauron as the most powerful yet evil character within the novel.

Tolkien is the 'higher self' of all of the above personas.
Tolkien projected himself to LOTR universe as Frodo, Legolas, Gandalf, Saruman and Sauron personas.
What is his purpose?
One need to ask Tolkien for the most correct answer, but generally it's because he wanted to make it 'interesting', at the very least interesting for him and maybe he wanted to explore the LOTR universe from multiple perspective.

A novel telling a story about a bunch of hobbits living peacefully in the shire will not be interesting isn't it?
Would a tv news aired a story about a bunch of people greeting good mornings to each others in the downtown area?
But tv news will definitely aired the story when suddenly a bomb exploded in that downtown area, disturbing the peace.

Thus if we take Sauron as the embodiment of STS entity within LOTR universe.
What kind of advice would Tolkien (the higher self) gave to Sauron? (which is also part of himself actually)
Well perhaps it's to continue exploring the path and play the role, although it's hard and not comfortable.

Why is that?
We all sometimes look for darkness in order to appreciate the light aren't we?
People goes to the most darkest place in the jungle or remote area in order to see the stars in the night sky.
An impossible thing to do within the lights of highly populated city or during daytime.