Autism Spectrum Disorder (ASD) has undergone significant diagnostic evolution, culminating in DSM-5’s unification of previously distinct conditions such as autism, Asperger’s disorder, childhood disintegrative disorder, and PDD-NOS—a move that simplified labels but obscured crucial differences. The historical trajectory reveals both scientific progress and persistent misunderstandings, while DSM-5’s framework introduces ambiguities, challenges in adult diagnosis, and…