To what extent does medication treat adhd symptoms in adhd people?

Varies: When medications are adjusted by a skilled professional it is often possible to achieve normailzation of function relevant to the adhd symptoms using one or more meds titrated to sufficient dose while watching for side effects. Very often there are other conditions that add to impairment and this makes treatment more challenging. Non-medication measure are always important as well.

Meds are effective : If the diagnosis is accurate, most adhd patients will respond to medications.