A psycho-genetic study of associations between the symptoms of binge eating disorder and those of attention deficit (hyperactivity) disorder.

OBJECTIVE Some recent studies have reported intriguingly strong correlations between ADHD and obesity. This study examined whether ADHD symptoms were more pronounced in adults with symptoms of binge eating disorder (BE) than in their non-binging obese counterparts, and whether the links were stronger with inattentive vs impulsive/hyperactive symptoms. We also assessed the role of the dopamine D3 receptor in ADHD symptoms since the DRD3 gene has been associated with impulsivity and drug addiction - both relevant features of ADHD. METHODS A case (BE: n=60) double-control (normal weight: n=61 and obese: n=60) design was employed. Assessments of both childhood and adults ADHD symptoms were made, as well as genotyping of seven markers of DRD3 including the functional Ser9Gly polymorphism. RESULTS Three DRD3 genotypes, including Ser/Ser, had significantly elevated scores on the hyperactive/impulsive symptom scale. In turn, the four ADHD symptom scales were all significantly elevated in the BE and obese groups, who did not differ from each other, compared to those with normal weight. CONCLUSIONS Results indicated a role for the D3 receptor in the manifestation of the hyperactive/impulsive symptoms of ADHD, and that symptoms of ADHD are significantly, but not differentially, elevated in obese adults with and without binge eating. Our findings suggest that ADHD screening in adults seeking treatment for obesity, including those with BE, may be warranted as methods used to treat ADHD may help some to better manage overeating and other factors contributing to weight gain.