Ritalin 20 mg is frequently thought of as the first choice for treating people with attention deficit-hyperactivity disorder (ADHD). Its precise mode of action for improving focus and attention is still unknown because it is a stimulant medicine. Still, scientists think it works by raising brain concentrations of specific brain chemicals, such dopamine and norepinephrine. Moreover, it may also increase serotonin activity, which could explain why it works so well for treating ADHD symptoms.