The Surprising Link Between ADHD and Obesity

A new long-term study of men with attention-deficit/hyperactivity disorder, or ADHD, has linked the disorder with an increased likelihood of becoming obese in adulthood.

The study tracked men with ADHD for more than 30 years and found that a whopping 41% of them were obese compared to 22% of patients in a matched control group who didn't have ADHD. The control group pretty accurately matches the general population, arguing there's something special about the high rate of obesity in men with ADHD.

The obvious explanation is that patients with ADHD have a hard time with impulse control. If you can't resist being the class clown, it's hard to resist eating that extra cookie.

Interestingly adults that had controlled their ADHD symptoms as an adult seemed to have a higher rate of obesity than those that continued to have symptoms. The results could simply be because the study was small -- there were only 111 in the ADHD group -- or it's possible those that have controlled their symptoms have developed a coping mechanism that involves overeating to stimulate the dopamine receptors.

Investment opportunity?
The men in this study were 41, so they were kids in the 1970s, long before drugs such as Pfizer's Quillivant XR, Eli Lilly's Strattera, Johnson & Johnson's Concerta, or Shire's multitude of ADHD drugs were available to treat the disease.

It seems reasonable to assume that if adolescence could control their ADHD, it might decrease their desire to overeat. There's some evidence for this hypothesis from another study that found children with ADHD who weren't taking medication were 1.5 times as likely to be overweight than those who took ADHD medications.

Companies that sell ADHD medications are in a constant battle with groups that think that children are being over-diagnosed and over-medicated. Avoiding obesity would add arsenal to the argument that treating with drugs is a better choice.

Of course, the companies have to be careful to not overstep their marketing. Side effects for some ADHD medications include reduced appetite and weight loss, which might explain why medicating reduces the likelihood of being overweight. But they're not approved to be used to treat obesity, so the companies aren't allowed to promote them for that purpose. In the fourth quarter of last year, Shire took a $57.5 million charge to settle an investigation of Shire's marketing practices for its ADHD drugs, although it didn't detail exactly what practices the Department of Justice wasn't happy about.

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The article The Surprising Link Between ADHD and Obesity originally appeared on Fool.com.

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