Is it in the DSM? I don't think so, but don't quote me on that. It's a commonly accepted belief that people on the spectrum do not have much empathy (the ability to feel what another person is feeling... sympathy, on the other hand, is feeling sorry for a person).
According to Mom, when I was a young teenager she caught a few isolated glimpses of empathy from me... but that was 10 years ago, and she hasn't seen any in a long time.
And to be honest, I wasn't sure I felt any, either. I mean, I kind of function "all about me." I guess that sounds selfish, and maybe it is, but... well, that's how I am despite putting forth great effort to feel for people. I can mechanically ask if you're feeling better after being sick, or I can ask my one staff if her back is hurting from walking too much, but really, it's not so much because I care as because it's what I'm supposed to do.
I asked Mom in the car how old I was when I first asked "how are you?" and she said, "You still don't." Well, yes and no. I certainly ask Leigh what's up (because I want to know what she's doing) and I ask Chloe how she is, but beyond that, I think Mom's probably right. Mom pointed out that I want to socialize, but when someone tries to start a conversation by asking me how I am, I say "fine" and walk away rather than reciprocate in any way. But then... chances are that I don't care how they are and don't really want to talk to them, unless it's one of my "inner circle" people.
Anyway, along these lines, feeling frustrated for myself for not really feeling any empathy, it was time to get Elsie Bo her medicine. I almost (and sometimes do) cry every time I have to give it to her because she hates it so much. And I can feel what it's like to be her and how awful it is. I am deeply empathic for my cat. Also, I feel very deeply for the cats in the shelter, stuck in their cages.
Not sure how to extend this to feeling for people... but I guess cats are a step in the right direction.