I will be interested to hear what people have to say about this, because I'm like this, but I never associated it with ADHD. I'm old enough that I took notes with pencil and paper when I was in college, and I found that the act of writing down the main points of what I was hearing somehow imprinted it on my brain. I have heard other people say that their brain works this way, too.

What you said about needing to understand the underlying concepts before you can remember something applies to me, too.

I have never been diagnosed with ADHD, and in fact, never even thought much about the subject until the last 4-5 years when I first started hearing comments from people about my inability to watch a movie, play a board game, etc.

I also have had lots of problems with forgetting things and losing things during my last episode of depression (which I suppose is still ongoing, but it has been much better for the last six months or so.)

I have been reading some books about non-drug methods to improve executive functioning and also about diet for the same thing.

I can look at my family members and see that ADHD type problems run on both sides of my family, although no one was ever diagnosed until one of my siblings was and now one of their children is.

Whether or not a person ends up with an ADHD diagnosis, I think it can be helpful to understand your style of thinking and learning. It sounds like you do, although I would encourage you to go to class for the social aspects of it and for interaction with the teacher/professor (unless it's one of those enormous classes with 100+ people in it.)