There isn’t any. Pseudologues (i.e., sociopaths who are also pathological liars) are the way they are born to be. Neither freewill or individual psychology plays any role. Their brains are even different (www.futurepundit.com/archives/001998.html, www.futurepundit.com/archives/003035.html.
However, there are other types of psychological liars so each individual should obviously be evaluated. A problem with this, though, is that those individuals we would assume to be experts, therapists, probably have less experience with pseudologues and sociopaths than we do in daily life. Pseudologues and sociopaths, being perfect in every way, simply do not often present themselves for treatment. Further, if they do, their purpose is not to change but to learn how to pass for normal more easily — in effect they seek to use talk therapy to become more adept as sociopathic predators.
I agree with those that believe pseudologues and sociopaths should never, ever be accepted into talk therapy. I would go even further to state that any therapists who do in fact do this should lose their licenses — since it is only by their being out of touch with their own soul that they could fail to recognize the soulless, could fail to recognize that they couldn’t reach the sociopathic client. Any therapist out of touch with their own soul can not be of any use to anybody, is by definition not even a therapist in the first place.
The worst situation I have ever known of in this regard involved a therapy group that allowed sociopathic members along with the depressives, neurotics, incest victims, etc. I’m sure the therapist (Nancy Becker, LCSW, http://nancybeckertherapy.com/, https://therapists.psychologytoday.com/rms/name/Nancy_Becker_LCSW_New+York_New+York_145736) would never have thrown piranhas into a goldfish bowl, but this she found acceptable. I’m not a fan of group therapy in the first place (I believe it is a grotesque lowering of boundaries before strangers one can not know) but accepting sociopaths into group therapy should be grounds for automatic malpractice suits against a therapist.
A universal among sociopaths (including pseudologues) is delight at manipulating the non-sociopathic into behavior betraying their souls.
In the instance above I consider the therapist to be a rigid or malignant narcissist herself (one of Scott Peck’s mentally ill evil described in his book, People of the Lie). Many people object to the concepts of evil and mental illness being joined, I can only assume they have never dealt with any malignant narcissists. Group therapy with such a flawed therapist would become a celebration of her defect. Sociopaths would effortlessly join that effort. In addition narcissists are very attracted to sociopaths, narcissists themselves have to spend eternity fighting their souls, their consciences, their dreams and do in fact wake up to their true humanity occasionally. Sociopaths have none of these problems.
A small grotesquery in an extremely grotesque story is that this therapist was called Mother by her clients. It is hard to imagine a greater perversion of reality or semantics.