I was diagnosed with anxiety and ADHD about 8 years ago, and since then, I have mainly worked on my anxiety. My anxiety has diminished drastically, and I have found that my ADHD symptoms are now manageable without medication (although I still struggle some days). For me, ADHD led to failing in my daily duties as a kid, which led to higher and higher levels of anxiety, which really exacerbated my ADHD symptoms. Now that I have learned how to control my anxiety, and with the resulting calming of my nervous system, the ADHD isn't nearly as problematic.

TL;DR: anxiety and ADHD are often intertwined and they spiral each other out of control, so what looks like ADHD is sometimes much worse because of anxiety.