I found this really interesting 2013 PhD dissertation by Zachary Wheeler from Pepperdine University.
It's written for clinicians specifically to help treat our condition.
It's titled:
Running Head: Treatment of Schizoid Personality
An Analytic Psychotherapy Handbook
It seems rare to find something so tailored for us so I'm hoping this will help the Psychforum community.
I've been sort of reverse engineering the work to understand myself and the condition better. I also printed a copy for my therapist so we can work on it together.
Here's the link:
https://search.proquest.com/openview/10cb591b9eb8147e5881ffc5bb279e66/1?pq-origsite=gscholar&cbl=18750&diss=yThat link is for the readable (and printable) website version.
There's also a button to download a PDF copy of the paper.