Good point. The number of diagnoses is also bound by mental health service capacity, which suggests that whilst in the past only very severe cases would be diagnosed, now many more are (as funding increases [1]).

The nature of health care also means that some of these conditions are "middle class" diseases, meaning that if you have the money to spend you can get diagnosed more quickly. There is some evidence of abuse of this, where wealthy parents get their children diagnosed in order to get school exams re-taken, etc. In general though, the diagnoses are spreading from the most severe to the middle of the range.

For those neurodiverse who can manage reasonably well in society by presenting well behaviourally, knowing ones own neurotype can be incredibly helpful, even if you do not take any further action after the diagnosis.

1. https://www.statista.com/statistics/252393/total-us-expendit...