It was actually through an Autistic person that I first learned about Sensory Processing Disorder (called Sensory Integration Dysfunction at the time). I was desparate to find answers about my light sensitivity problems and found only references to it by Autistics.

Since then, I have found out that SPD is a common problem for people with other health problems and the more out of control those conditions get, the worse sensory problems will get.

I have always had some sensory problems, but they didn't make my life more difficult until I was an adult and my Food Allergies and Hypokalemic Periodic Paralysis were heavily active. Now they work together to make my life more challenging.

I think for Autistics the Sensory problems make the handling input more difficult so that they have a hard time changing their own environment to work at their peak performance levels. SPD kids without Autism are able to eventually explain what is bugging them enough to get the problem to stop. When I was a kid, I explained to my parents that certain clothes were unacceptable. I couldn't seem to explain that they burned my skin, but I did get them to stop forcing me to wear clothes that hurt me. Same thing for foods that caused me a lot of pain and projectile vomitting.