So for example, in the case of ADHD, we discovered that there are dozens of different diseases, all of which had been called ADHD at the start of the century, that actually had nothing to do with each other, except that they had similar symptoms.
Por ejemplo, en el caso del TDAH, descubrimos que hay decenas  de enfermedades diferentes, que, a principios de siglo,  eran conocidas como TDAH, pero que no tenían nada  que ver unas con otras, excepto que tenían síntomas similares.