Internal workings of ADD medication

I have been trying to understand ADD/ADHD for some time, and please pardon my ignorance.  My question, however, relates more toward the medications used to treat the disorder.

What is the effect of a stimulant on ADHD.  For instance, it seems to me that ADD/ADHD are disorders caused by overstimulation, rather than understimulation.  Therefore the use of Dexadrine to treat ADD or ADHD would only worsen the problem; although it is obvious that it is a very good treatment.

To sum my question up:  What is the actual neurological effect of the stimulants, in particular, Dexadrine?

Thanks
Tony

[HFHS M.D.-SW]

Dear Tony,

Your question has intersted Neurologists, Neuropsychiatrists and Psychiatrists for years. Sadly, the exact mechanism of action is unknown. The idea of a paradoxical response in hyperactive patients is no longer accepted.
What is known, is that treatment is available.  The medications of choice are Ritalin, Dexedrine, Adderall (adderrall) all are psychostimulants. There are numerous other drugs with different mechanisms such as, clonidine and buproprion.
The cause of ADHD/ADD is uncertain.  Some studies report possible genetic link others report possible social contributing factors.
Studies have shown medications and psychotherapy to be effective.
Hopefully with more research the mechanism will be better understood.

Sincerely,

HFHS M.D.-SW

*Keywords: Ritalin, Dexedrine,