Genes Outrank Environment In ADHD-Related Binge Eating Disorder and Substance Abuse
The argument of whether nature or nurture drive our behaviors and play the overriding role in determining our personalities, behavior, and wellness has been raging for centuries. It is clear that both our genetics and our upbringing influence our lives in profound ways, but many believe one of the two may be more influential than the other.
A new doctoral thesis from Linköping University is adding fuel to the debate with its conclusion that hereditary factors and genetics are the primary factors determining how susceptible a person is to ADHD and co-morbid alcohol dependence and binge eating.
Andrea Johansson Capusan, consultant in psychiatry, noted that binge eating and alcohol dependence are significantly more common among adults with ADHD symptoms and sought to investigate how much of the increased risk can be linked to hereditary factors compared to environmental factors.
Using the Swedish Twin Registry, Capusan was able to compare identical twins with 100% matching genes to fraternal twins, whose genetics are as distinct as typical siblings.
To determine whether genetics or environment are stronger influences on ADHD and related health issues, Capusan examined past studies assessing whether correlations between ADHD and co-morbid substance abuse or binge eating disorders were stronger among fraternal or identical twins.
The thesis included four studies including more than 18,000 twin pairs aged between 20 and 46-years-old using questionnaires regarding consumption of alcohol, substance use, and binge eating behaviors.
“We have shown for the first time that the correlation between ADHD symptoms and binge eating in women depends mainly on a common hereditary susceptibility for the two disorders. Much of the correlation between alcohol dependence and ADHD can also be explained by genetic factors. The remainder of the correlation is explained by environmental factors that are particular for the individual, which is interesting. It seems that having a common environment while growing up is not significant,” says Andrea Johansson Capusan.
Since the evidence suggests heredity plays such a large role, Capusan suggests that health professionals should take extra steps at early points in patients’ lives to prevent these conditions from developing later in life. “When treating adults who come with dependency disorder or substance-abuse behaviour, it’s important to remember that ADHD is very common in these patients. And conversely-it’s important to treat ADHD early in order to prevent alcohol dependence and binge eating later in life,” says Andrea Johansson Capusan.