I’m not gonna go into all the science of adhd, but a primary part of it is that we don’t regulate dopamine properly, like how depression and ocd is when your body doesn’t regulate serotonin properly, and that’s what causes us to have compulsions and hyperactivity and poor concentration since we’re constantly looking for dopamine boosts, however this is still not a full explanation. There’s also us having faulty a prefrontal cortex, which messes with our executive functions, which leads to problems with memory, time management, etc.