Dopamine |
| Animal studies initially suggested dopamine depletion in the CNS to be the biological basis for AD/HD. Rat pups with CNS dopamine deletion were found to be more active than their control litter mates(4).
Stimulants (methylphenidate, pemoline,and dextroamphetamine) increase the release and inhibit the reuptake of Dopamine raising dopamine levels in the CNS (5,6). Depletion of dopamine in CNS pathways cannot be the full biologic explanation for AD/HD because dopamine agonists (e.g. L-dopa) are not effective in the treatment of ADHD(7). Additonally, some drugs which are dopamine antagonists (haloperidol, cholpromazine and thioridazine) have modest positive effects on AD/HD symptoms(8,9). |