I have a close friend whose daughter has it. From what I understand she can’t weigh consequences out beyond about 2 minutes. Current emotional discomfort (like being slightly bored) is over the top painful. She can’t deal with “no” sometimes, like she goes so crazy the police have to be called sometimes. I read that it’s kind of like if you had no skin and thus all your nerve endings were exposed. Sitting would hurt, a breeze would hurt, sunlight and rain would hurt. But she can go from screaming and throwing punches at her parents to being their darling little daughter five minutes later as though nothing had happened. I suspect she can’t relate at all to others’ experiences - it’s just her. She seemed like a totally normal kid until puberty hit.