My understanding is that the ADHD brain activity resembles an NT's when they're extremely tired or sleep deprived, with a lot of theta wave activity. Stimulants can help jog an ADHD person's brain into alpha and beta waves, which are associated with relaxation or alertness and focus.

[–] rhombus@sh.itjust.works 1 points 3 hours ago

It’s a bit of both with a healthy dose of “we’re not sure”. We know that ADHD brains don’t regulate neurotransmitters properly and that the theta vs beta waves are different, but there are a lot of other mechanisms we don’t understand.

Another great example is guanfacine. It’s primarily a blood pressure medication, but it also improves emotional regulation for ADHD patients. We think it improves connections in the prefrontal cortex, but we ultimately don’t have a solid understanding of why it actually helps.