In a nutshell, yes.
Think about this with other meds - like antidepressants. One WITH depression (for example) will take an SSRI and experience nothing more than the regular side effects such as trouble sleeping or vivid dreaming, night sweats, etc. However, one without depression may experience a shit ton of effects because his/her body is more chemically balanced and when the drug is ingested, a different response is triggered. The SSRI is not NEEDED, and is therefore not accepted and utilized in the same manner as with the person WITH depression and a chemical imbalance (if one is had).
*People WITH add/adhd (and a chem imbalance, pos) experience a different reaction when the drug, a stimulant, is ingested. The body doesn't speed up and go crazy but rather - slows down and things become more clear. If the opposite were true, they would not be prescribed for such a purpose. When a person withOUT add/adhd takes a stimulant (the same stimulant) they have a different chemical/genetic make up and have a response that DOES include that 'speediness'.
There are many of variables that make this answer vary. This is a generalization and certainly doesn't ALWAYS apply.