Your post is interesting - because I chose PM&R precisely because I found other fields depressing. I initially thought I wanted to do internal medicine - but I got depressed about all the social issues and patients who kept coming back after we temporarily made them feel better. I then considered Neurology but after the interesting discussions about where the lesions could be and the pathophysiology/anatomy behind the symptoms we were seeing, we could not do anything to make them better.
I felt like rehab was a happier place. Patients are there to get better. They have to be motivated - and they make amazing progress and it's really fulfilling to share their successes with them. Even SCI patients can be uplifting to care for - as they learn how to deal with their new disabilities. You can do minor procedures to make them feel better quite quickly - like spasticity treatments, etc. In addition, the outpatient side of things can be quite fun and exciting. Who can find sports medicine depressing?
Sure it's hard to see young people whose lives are destroyed by SCIs or TBIs - but you also get to see them get better and develop relationships with them. Remember, they are technically supposed to "qualify" for rehab - so they have to be medically stable.
Anyways, I would also echo the recommendation to do a rotation or at least spend a couple days in a rehab to see what it's like instead of taking other people's words.
