I just get angry at the thought that not only does autism affect our brains it also affects our immune systems and digestive systems. When something becomes physical like that, it can border on to disease.
If autism was just a neurological disorder like it used to be when I first got diagnosed then I wouldn't call it a disease. Now all these physical things are associated with it too, it makes me squirm.
It's all in how one internalizes it. Myself, working in healthcare for as long as I have, and dealing with genetic conditions within the neonatal unit, I tend to have a different take on the subject and where to place autism within the spectrum of genetics. As an ASD-1/Asperger's variant, relatively speaking, I am doing pretty well. Granted, I DO have some GI issues, neuromotor, and immunological aspects to my condition, but again, relatively speaking, pretty manageable now that I am aware of them.
Medical terminology is a funny thing. What medicine calls a "disease" is a HUGE umbrella of conditions. In the neonatal unit, when a baby is born with abnormal anatomy of the heart, it falls under the category of congenital heart disease (CHD), but IS IT a disease? That's up to the perspective and context. Is a mental health condition a disease? It depends upon the underlying cause, but in medicine, regardless of the cause, it is under the umbrella of mental health disease. Cancer is a disease. Cystic fibrosis is a disease. Pneumonia and other infections are diseases.
A definition of the word "disease" within the context and perspective of medicine would be:
"An abnormal condition that adversely affects the structure or function of all or part of an organism and is not immediately due to any external injury. Diseases are often known to be medical conditions that are associated with specific signs and symptoms."
So, is autism, by the above definition, a disease? Yes. Sorry if that hurts peoples feelings, but it is what it is,...by that definition. Now, obviously, there is a lot of variables to consider. With empathy towards all my autistic brothers and sisters out there, an ASD-1 is not in the same category as an ASD-3 individual. Personally, I typically use the language "condition" as in "I have an autism or autistic condition" and do not use the "disease", per se, because, as we know, "disease" within the realm of common, everyday, layperson's language implies something more significant. I know, it gets really fuzzy and how people interpret language can vary.
At any rate, I wouldn't get too hung up on the medical terminology and give it much thought,...seriously. Brush it off. I happen to know enough about the condition and live with it, like many of you. I don't walk around thinking I have a disease. All we can do is be aware of the autism science and research, learn a few things about ourselves, adapt and overcome. Stay positive out there kids.

