Hyperfocus is also a symptom. It's a strange thing, ADHD. They won't give me stimulants or antidepressants any more either. They have a problem with me being in mania or hypomania and don't like that. I don't like the fallout of them, but quite like most of the manic symptoms.
I'll not press it further. Bipolar causes focus issues too, in any mood, and the meds for it certainly do.
I have a way you can test your focus. This isn't for any condition in particular, just a focus test. Find a puzzle game you like to play, like Sudoku. Do a puzzle three times a day, morning, noon, and night. Make it something you can do very quickly. I test with 12x12 but I'm ADHD with hyperfocus so don't go that far to start with or do it if you can. My best time is under 12 minutes and longest is in the evening at more than 112 minutes with finally giving up.
I do have to use caffeine and other stimulants found in nature and energy shots/drinks to barely keep focus. I found the Eternal Energy shots that only Walmart sells to work best, because they also give minor seratonin boosts with yerba mate