Obesity, attention deficit-hyperactivity disorder and the dopaminergic reward system.

The obesity epidemic has focused attention on obesity's health consequences beyond cardio-vascular disease and diabetes. To evaluate the potential consequences of obesity for Attention Deficit-Hyperactivity Disorder (ADHD), we surveyed the literature. Current findings link both obesity and ADHD to the dopamine system and implicate dopamine genes in body weight, eating, and ADHD. Detailed consideration suggests that dopaminergic changes in the prefrontal cortex among individuals with the ADHD subtype Attention Deficit Disorder (ADD) may increase their risk for obesity. Thus, individuals and populations with a high prevalence of hyperdopaminergic genes may experience higher rates of obesity in the presence of abundant food. From an evolutionary perspective, alterations in the dopamine system appear to effect a wide range of behavioral phenotypes. We suggest that recent evolutionary changes in the dopamine receptor genes selected to increase cognitive and behavioral flexibility may now be associated with attention problems and increased food consumption in an obesogenic environment.