In response to yesterday’s post on ADHD and obesity, I was made aware of two recent studies, both relevant to this topic.
In the first, A psycho-genetic study by Caroline Davis and colleagues from York University, Toronto, Ontario, Canada, published in the Journal of Psychiatric Research, the researchers 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. They 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.
In the study that involved 60 cases and 120 controls (60 obese and 60 normal weight), childhood and adults ADHD symptoms were assessed and genotying was performed.
While all of the four ADHD symptom scales were significantly elevated in the BE and obese groups compared to the normal weight group, bearers of three DRD3 genotypes had significantly elevated scores on the hyperactive/impulsive symptom scale.
These results suggest that symptoms of ADHD are more common in obese individuals (irrespective of BED status) and that the D3 receptor may play a role in the manifestation of the hyperactive/impulsive symptoms of ADHD.
In another study, published in this month’s issue of OBESITY by Lance Levy and colleagues from the Nutritional Disorders Clinic, also in Toronto, Ontario, Canada, they describe their success in treating refractory obesity in severely obese adults following the management of newly diagnosed attention deficit hyperactivity disorder.
78 subjects out of 242 consecutively referred severely obese, weight loss refractory individuals were diagnosed as having ADHD, of which 65 received ADHD treatment and 13 remained as controls.
After an average of 466 days of continuous ADHD pharmacotherapy, weight change in treated subjects was -12% of initial weight versus a 3% weight gain in controls.
This study not only confirms that ADHD is a highly prevalent condition in severely obese patients, but that the treatment of ADHD is associated with significant long-term weight loss in individuals with a lengthy history of weight loss failure.
Levy suggests, as I did in earlier postings on this topic, that ADHD should be considered as a primary cause of weight loss failure in obese patients.
As he points out, this finding may also be important for patients seeking obesity surgery, as surgical patients with unmanaged ADHD may display poor compliance with diet and supplement requirements.