The fields of ADHD and autism and how we understand, diagnose and support these populations have evolved tremendously over the past 20 years. The diagnostic criteria have changed in both conditions over the years, as well as our understanding of how ADHD and autism are expressed across the lifespan, gender and levels of functioning. The internet and public discourse, the disability rights movement, and advances in clinical practice and research have impacted how we understand individuals in these populations and the overlap or co-occurrence of ADHD and autism. This session will help to describe the basics of diagnostic criteria, diagnostic methods and evolution in the fields of ADHD and autism, as well as try to sort out some of the confusion and misinformation out there making it all so difficult to understand.