Attention-deficit-hyperactivity disorder and reward deficiency syndrome.
Molecular genetic studies have identified several genes that may mediate susceptibility to attention deficit hyperactivity disorder (ADHD). A consensus of the literature suggests that when there is a dysfunction in the "brain reward cascade," especially in the dopamine system, causing a low or hypo-dopaminergic trait, the brain may require dopamine for individuals to avoid unpleasant feelings. This high-risk genetic trait leads to multiple drug-seeking behaviors, because the drugs activate release of dopamine, which can diminish abnormal cravings. Moreover, this genetic trait is due in part to a form of a gene (DRD(2) A1 allele) that prevents the expression of the normal laying down of dopamine receptors in brain reward sites. This gene, and others involved in neurophysiological processing of specific neurotransmitters, have been associated with deficient functions and predispose individuals to have a high risk for addictive, impulsive, and compulsive behavioral propensities. It has been proposed that genetic variants of dopaminergic genes and other "reward genes" are important common determinants of reward deficiency syndrome (RDS), which we hypothesize includes ADHD as a behavioral subtype. We further hypothesize that early diagnosis through genetic polymorphic identification in combination with DNA-based customized nutraceutical administration to young children may attenuate behavioral symptoms associated with ADHD. Moreover, it is concluded that dopamine and serotonin releasers might be useful therapeutic adjuncts for the treatment of other RDS behavioral subtypes, including addictions.
Blum
Kenneth
K
Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA. drd2gene@aol.com
Chen
Amanda Lih-Chuan
AL
Braverman
Eric R
ER
Comings
David E
DE
Chen
Thomas J H
TJ
Arcuri
Vanessa
V
Blum
Seth H
SH
Downs
Bernard W
BW
Waite
Roger L
RL
Notaro
Alison
A
Lubar
Joel
J
Williams
Lonna
L
Prihoda
Thomas J
TJ
Palomo
Tomas
T
Oscar-Berman
Marlene
M