I want to point out that there are currently more than 450 mental disorders - this is a massive amount! I have included an excerpt below from the Wikipedia page which sets out this controversy and provides a current list for you to peruse
Just like the Mood Disorders, the Anxiety group has many different flavours. And like depression, anxiety will accompany ADHD, whether you can pin any of the sub-categories badges to your chest or not.
ADDers will drift through their day wondering whether they are in the right place, do they have what they need, why have they arrived in a room or a place, or even what they have to do there.
This is anxiety in it’s purest and most basic form. The level of this anxiety will fluctuate throughout the day, and the week. Eventually it becomes the norm.
This anxiety is related to short-term, or working memory. So even if you have just read what the next task is in your diary, within a few minutes you will have forgotten what the next task is.