Help please! is autism spectrum disorder an actual disease or just a name of a group of disorders?

It is a spectrum: There is no clarity on what exactly causes those very similar in presentation -and therefore easy to confuse- disorders. They are not then (technically) diseases in the classic sense. For example, autism might well be a disease, but to declare it we would need science to tell us exactly how, why it happens; which nobody really established for sure yet. Many theories tried to explain it, though.

Group: This is a collection of different issues based on abnormal intellectual, communication or developmentall problems. It includes autism, Asperger syndrome and pervasive developmental delay not otherwise defined.The classification is a needs based one rather than on origin.Classification allows schools and therapists to get appproval for the special therapy they require.