An aspect some people don’t realize people with ADHD deal with is sleep. Be it being unable to fall asleep, stay asleep, and are at a higher risk of developing insomnia among other sleeping disorders.
78% of adults with ADHD have issues with their circadian rhythm, and 70% of kids with ADHD have trouble falling asleep. As mentioned in the video linked below, there is a bit of a chicken and egg situation: is ADHD causing sleep disorders in people, is the sleeping issues aggravating the ADHD, or is it a mix of both?
Sleep onset insomnia is more present in people with ADHD (with hyperactivity) as opposed to people with ADHD who are mostly inattentive.
Another article I read was talking about how nightmares in children with ADHD was pretty common, which was actually another big issue when I was growing up. I spent most of my elementary school bed times walking up crying for my parents because I had a nightmare. I didn’t really expose myself to horror movies since I was a bit of a scaredy cat for some things, but it was pretty normal for me to have nightmares up to twice a week on the regular.