Welcome to PC.... and to the forum....
Sorry... I don't know anything about a disassociate disorder from non trauma... perhaps someone here on PC... knows... and a T... if you have one...
My guess is that a person could have a dissaciative disorder from non-trauma... because all people dissociate to some degree.. like in driving... and my guess... is that some people may just get very good at using that "tool" - disassociation... when they want to leave a situation... because in my opinion... that is what disassociation is.. a tool...