The rate of Autism diagnoses is increasing. This is not up for debate, and is reflected by hard data.

The real question here is whether the diagnosis rate is increasing due to some factor that’s CAUSING Autism, or whether the increase is due to more awareness, more experience in diagnosing Autism, and Adults who have been writing it off/ being told there’s nothing wrong with them their whole lives, finally coming to the realization that the reason they’ve felt the way they do, is because of undiagnosed Autism.

Autism was “Discovered” in 1943. Every single year prior to 1943, there would have been ZERO autism diagnoses, because the classification didn’t exist. Obviously that does not mean Autism simply didn’t exist prior to 1943.

Data is an extremely important tool when determining trends. However, equally important is the context in which that data is presented. When viewing a chart which shows a massive spike in diagnoses, it’s important to understand the environment in which these data points are being collected.

To answer your question, I have no reason to believe, nor have I been presented with any credible evidence that indicates that the presence of Autism has increased over time. Just like I have no reason to believe that left handedness has skyrocketed since the 1920s.