This is a modified repost from a post we made on TrevorSpace.
Not only that, but they're recognized by the same people who made the DSM-5
Serious! We have screenshots!
The APA made the DSM-5, the widely used diagnostic material for DID and OSDD, among other mental disorders.
Dr. Eric Yarbrough, distinguished member of the APA, published a text called "Transgender Mental Health" (that we couldn't track down on archive.org T_T).
(Sorry the second one is blurry, we couldn't find a better quality image.)
The DSM-5 was published by the APA (American Psychiatric Association) in 2013; Transgender Mental Health by Dr. Eric Yarbrough, "Distinguished Fellow" of the APA was published in 2018.
TL;DR: Endogenic systems have been recognized by the same people who made the DSM-5 for 5-6 years now.