Yes, i believe that you're brain being sped up means that your brain can think out the consequences of its actions more completely before actually doing it. Also, stimulants just tend to raise inhibitions.
Add is caused by low dopamine levels mostly, so med bring them up to normal. When on aderall(rx dosage) its impossible for me to sleep, but my brain is clear and I can actually string thoughts together. We can get "high" off our meds, but personally to feel "high" and "energetic" from it I would have to take many times my dose.