When making headcanons or writing characters with ADHD, something to consider is that the “hyperactive” is sometimes not actually the way it’s commonly perceived. (It’s different from case-to-case.) Hyperactive could mean general restlessness without being particularly energetic, and can even cause fatigue (most likely because of lack of sleep). Fidgeting, shifting in their seat, leg bouncing, the need to get up frequently - not hyper, but a need to move in some capacity.
There are a lot of different aspects of ADHD other than the restlessness. As an example, imagine Kenma with ADHD:
- Kenma playing games to split his attention to help focus, otherwise he’s more likely to zone out or get sidetracked.
- Kenma getting great grades in class, but not doing so hot in school overall cause he genuinely forgets his homework all the time. And forgets to check his reminders. And gets sidetracked if he does check them.
- Kenma getting overwhelmed in crowds (overstimulation) and coping by hiding off into a corner and distracting himself with his PSP.
- Kenma being unable to stay in the same area - like a store or particular room - for too long without feeling frustrated and antsy.
- Kenma having a hard time with most puzzle games, or games with long tutorials.
- Kenma finding a puzzle game that’s just right, that he plays constantly cause it helps him relax.
- Kenma never replying to texts cause he gets sidetracked after reading and forgets to respond.
- Kenma playing video games cause it’s the only thing that keeps his mind from constantly racing.
- Kenma considering growing out his hair longer than he’d like cause he just keeps forgetting - for weeks or even months at a time - to go get it cut.
- Kenma feeling tired all the time cause he stayed up too late staring at the ceiling cause his brain wouldn’t shut up - then when he does sleep, waking up at a ridiculous time to play that game he spent all night thinking of strategies or new characters to create in it.
ADHD is complex, and wow that turned out really long, I wrote way too much there. Anyway, I hope Kenma as an example helps anyone who’d like to write or hc more ADHD characters!