There's much less of that in medieval times than what TV would have you believe. Plenty of people were just labelled "crazy" or "weird" and few made a wide enough impact to attract the ire of people who actually cared enough to kill someone.

The fact that ADHD is hereditary should tell us how few were killed for it.

People forget that humans are social creatures, we don't just up and kill anyone who is different (as a rule). We also have barely changed since medieval times, so sympathy and empathy are just as present now as they were back then - we just have a better understanding of things now and so we think we are labelling things a bit better than we were a few hundred years ago. And in another few hundred years we'll be better at labelling still. But we'll still be labelling.