It's often more about _how_ you discuss something, rather than what the underlying topic is. I can see abuse or sexual discrimination being in an essay if..
-the experience is very relevant to your decision to go into medicine or the development of your thoughts that pertain to the question being asked
-your handling of the topic reflects maturity, compassion, and intelligence
-it's not the only thing you talk about...if it's in a long essay where you could reasonably move to other areas. if it's a short essay, you might not have enough room to handle a sensitive topic well at all.
So, the stakes are higher, but incorporating these sensitive experiences (given their strong influence on your life or thoughts) can help you create a stronger essay thats more true to your motivations.
Personally, I brought up two sensitive topics (for me at least) in my personal statement, and in some cases brought up other aspects of those experiences again in some secondary essays.
However, I think in some cases I achieved what I outlined above, and in others I did not. Where I constructed my thoughts well, it was a real strength. In the cases I didn't, well...let's just say I haven't heard from those schools yet :0
I echo drlexygoat and Alexander99's point - I've only had 1 interview where I wasn't asked about either of the two experiences I mentioned in my essay and had to discuss it at some depth.