THE MOLECULE OF MOREwith ADHD have difficulty making friends. Who wants to be around
someone who interrupts, grabs things, and doesn’t wait their turn?
They often have to read homework assignments over and over again
before they understand the material. This happens as a result of con-
stant distractions. Spending that much time on homework doesn’t leave
much time for extracurricular activities, such as sports and clubs. With
few friends, poor grades, and cut off from healthy sources of pleasure,
children living with untreated ADHD become more willing to pursue
unhealthy sources of pleasure. In addition to drugs, they may also have
problems with early sexual activity and overeating, particularly “plea-
sure foods” that are high in salt, fat, and sugar.
A massive study involving 700,000 children and adults, including
48,000 with ADHD, found that children with ADHD were 40 percent
more likely to be obese, and adults were 70 percent more likely to be
obese. At nearly three-quarters of a million participants, with data
taken from cultures around the world, the study was not only greater
in size than most investigations of its type but also far more diverse,
allowing the scientists to compare the results from different countries
where one finds a variety of diets and eating rituals. Yet, in spite of the
differences in diets among, for instance, Qatar, Taiwan, and Finland,
the findings were the same. Country of residence did not affect the
relationship between ADHD and obesity. There was also no difference
between men and women.
Despite the strengths of this study, there are weaknesses as well. Just
because we find that people with ADHD are more likely to be obese
doesn’t necessarily mean that having ADHD causes obesity. What if it
was the other way around? What if being overweight somehow affected
the brain in a way that caused ADHD? The fancy scientific term way
of saying this is association does not imply causation. Just because two things
are found together doesn’t necessarily mean that one caused the other.
We’d have more confidence that ADHD leads to obesity if we could
show that people develop symptoms of ADHD before they become obese.
So researchers from the Universities of Chicago and Pittsburgh eval-
uated nearly 2,500 girls to find out if there was a connection between
unhealthy weight and problems with impulsivity. The lead researcher