I think it does depend but there is something approximating an absolute distinction. For example low functioning autism or severe schizophrenia would be debilit

I think it does depend but there is something approximating an absolute distinction. For example low functioning autism or severe schizophrenia would be debilitating in all but the most advanced societies. However, high functioning autism or mild schizotypal/schizoid disorders probably would not be debilitating unless the society had a low tolerance for eccentricity.