Anxiety is a slippery beast, because it can be a characteristic of some other condition, or its own condition.
My diagnosis yonks ago was Anxiety Disorder Not Otherwise Specified, and I think it was spot on. My anxiety manifests in all kinds of ways and changes frequently. Generalized anxiety, yes. Night terrors, yes. Social anxiety pretty much always. I once went through this heinous 2-3 month cycle of intrusive thoughts around a very specific image and situation after seeing a graphic photo in the news. I relived the same moment over and over in vivid detail every night and was getting no sleep. Unfortunately I have a really vivid imagination (good for writing, I guess.)
You know how I got though it? I designed my own exposure intervention. I sat down and journaled about it in excruciating detail in the most upsetting way possible and I did it over and over and over until it didn’t bother me any more. I later did the same thing after a brief altercation I had with a cyclist where I wasn’t sure who was at fault. I was agonizing over it and I couldn’t let it go. So I just sat down and let the worst fears and feelings manifest. Yes, this means you are a piece of shit and are worthless and deserve a lifetime in prison etc. And I looked at it and realized how disproportionate my reaction was to reality and that it was probably unrelated trauma. And then it didn’t bother me so much anymore.
This week I’m obsessing over what it might be like to die. It started when I read an article about Nazi Germany.
My anxiety is a lot better than it used to be.
Oh but I’ve read people with ADHD and autism have a harder time setting this kind of thing aside. Because we have a tendency to hyperfixate on things. I have very very powerful tendencies toward hyperfixation for days or weeks. Sometimes it’s helpful, like when I’m writing a novel, sometimes it’s neutral, like the time I spent obsessed with the 1996 Mt Everest disaster, and other times, it’s hell.
So when you look at my anxiety, it probably would have been there independent of ADHD but it’s also clearly exacerbated by ADHD. I’ve also read that people with ADHD have a greater tendency to recall random negative events from the past. Fold that into PTSD.
I do believe these things can exist discretely, such as having different causes, but I think by nature they are interdependent.
But to answer your question @Dinsdale the DSM is pretty agnostic to the cause of a disorder, and it would be unusual and against standard practice for a psychologist to diagnose someone of anything if they didn’t meet the required criteria. That would include comorbid diagnoses. Someone would have to meet the criteria for both disorders to receive both diagnoses.
It used to be you could not be diagnosed with both ADHD and autism. Clinicians had to pick one. That is no longer the case. It actually turns out the comorbidity of ADHD and autism is extremely common.