Check out Dr. Greenberg on Quora

She writes a lot on schizoid PD, NPD, and borderline PD. She is a gestalt therapist and believes all of these, despite being known as really difficult to treat, are treatable and can show improvement with the right therapy and if the person actually wants to change. 

She is the author of the book "Borderline, Narcissistic, and Schizoid Adaptations: The Pursuit of Love, Admiration, and Safety."