Most of the few people I have personally known who transferred did so because their mentors all left the institution for other jobs and no one was left to educate them anymore at their home institution. Other programs stepped up to take these “orphaned” residents in and the original institution helped fund their salaries at the new institution.
I know of a couple people who transferred or left because of bullying or other interpersonal issues between reisdents and mentors or other staff members, but those are less common. One of my residentmates looked into possibly transferring because she didn’t want to stay in our program, but there were no openings and ended up just leaving the specialty altogether instead and returning to GP. Another person who left my program before I got there pretty much had to start all over and do three entire years at the new school. Most places aren’t just going to have an opening to take someone in on a whim. And if a place is looking to replace someone mid-program, I’d definitely want to know why the heck someone quit and why there is suddenly an opening. If they were to add to a program off cycle (meaning no one quit, they’re just adding you), I imagine it would just be because the program is so busy and they need more bodies to do the work, which isn’t going to solve your issue of feeling like you have too many cases at all. Most places operate house officer programs in a tight budget so they can’t (or won’t) just create new programs willy nilly.
Ultimately, I agree with shorty…I think it’s unlikely you’ll be able to find a program to transfer to for these reasons. Maybe if you already had strong ties to an institution, but probably not just anywhere. If you were to transfer there may be some gossip but long term effects would probably be fairly minimal other than talk. But I just don’t think this will be considered a valid reason to transfer (even though mental health should be important).
I think you’d potentially have more luck talking things over with your residency coordinator and see if they can reduce your caseload or something, even if just temporarily. Surely they’d rather you be there seeing some cases than having to replace you. It wouldn’t be an easy conversation but I would explore that first.
Residency is tough. I love my job but I wouldn’t want to go back to being a resident. Sorry you’re having such a hard time, but I promise you’re not alone in being overwhelmed. It gets light years better on the other side if you can hang in that long.