Ari Tuckman, PsyD, MBA* –
What Causes ADHD? –
It’s more nature than nuture. Research has found that ADHD is primarily caused by genetics, although environment may also play some role. So it’s more about who your parents are than how they raised you (although their parenting style may affect whether you develop any of the conditions that tend to come along for the ride with ADHD).
About one in four first-degree relatives (parents, siblings, and children) of someone with ADHD also have ADHD. In practical terms, we can therefore assume that if someone has ADHD, there is a very good chance that at least one other person in the family has it as well.
This makes ADHD one of the most heritable mental health conditions, up there with bipolar disorder and schizophrenia. Researchers are still working on identifying all of the genes that are involved, since there are likely about half a dozen, each of which contributes in its own way.
Of course, as with most conditions, there is still some room for environmental influences. Since ADHD is a brain-based disorder, anything that affects brain development in pregnancy or during early childhood could have the potential to affect whether someone develops ADHD and how severely.
This can include prenatal exposure to nicotine or alcohol; early exposure to lead, stroke, brain trauma; and low birth weight. Maternal smoking has been found to be the strongest predictor of ADHD symptoms in children (Barkley, 2006a).
However, this may be an indirect effect in that ADHD children are more likely to have ADHD mothers who are more likely to smoke. So the smoking itself may not cause the ADHD in the child. Things like parenting style and socioeconomic status have very little effect on who displays ADHD symptoms.
Things That Don’t Cause ADHD
Even though solid scientific research has proven what does and doesn’t cause ADHD, there is still a lot of information out there about supposed causes that either have no scientific support or have been disproved. So let’s go through those, since knowing what isn’t true can be as important as knowing what is.
Diet and Food Additives
Probably the best-known unsupported theory is that ADHD is caused by diet, such as refined sugar, food additives, food allergies, or vitamin or mineral deficiencies. Refined sugar and artificial food colorings, in particular, gained notoriety from supporters of the Feingold diet. Of course everybody does better with a healthy diet, but study after study has found that diet does not create ADHD.
A small minority of people may have reactions to certain foods that make them feel less focused, but ADHD involves far more than that. So, to state the obvious, if you find that certain foods affect you negatively, don’t eat them.
Some of the confusion related to these diet theories is that many studies have indeed found that ADHD kids tend to eat more junk food. There are two reasons for this.
First, impulsive ADHD kids may not delay gratification well and therefore are more likely to eat unhealthy foods that taste good. Second, ADHD kids are more likely to have an ADHD parent who will have a harder time doing the extra work that eating healthfully entails—junk food tends to be easier.
So, in both cases, having ADHD causes the eating of junk food more than junk food causes ADHD. These early researchers were right in what they measured, but they got it reversed in what caused what.
The bottom line here is that changing your diet to treat your ADHD is a waste of time. It’s good for you in other ways, so there’s no harm in it. But focus on proven treatments. In a way, if you’re able to maintain a generally healthy diet, it probably means that overall you’re doing pretty well with your ADHD, since it takes stability and consistency to eat healthfully.
Probably every parent of an ADHD child has received comments that a better parenting style would get that kid to behave. This only adds insult to injury—not only is that parent struggling with raising a more challenging child, but the comments blame the parent for those challenges!
Even when said in a supportive way and with good intentions, these comments can still increase feelings of helplessness and frustration. This is especially true for kids who were born before 1970; at that time ADHD was not well known, so those parents had to figure things out on their own, just as you did. So just as you hopefully cut yourself some slack once you learned about your ADHD, cut your parents some slack too (especially if they also had undiagnosed ADHD).
Just as with the early research done on diet, the researchers were right about what they measured, but they got the causes reversed. That is, ADHD kids cause bad parenting more than bad parenting causes ADHD, so the researchers measured the result rather than the cause.
Untreated ADHD children are better at pushing their parents past their limits, so those parents use fewer positive behavior-management techniques and more negative ones.
As further proof, some really interesting studies have found that when ADHD kids are prescribed medication that controls their problematic behaviors, their parents wind up using more positive parenting techniques and fewer negative ones (Barkley, 2006b).
Amazing—the parents perform better when their kids take medication! Of course, most of the parents of the ADHD kids in my practice could have told you this, too.
A third theory holds that the sometimes frenetic pace of modern life makes us all more distractible and hyperactive and even gives some people ADHD. This is used to explain why ADHD seems so much more prevalent now than it used to be.
As much as our electronics-driven information overload can distract even the most single-minded among us, there simply is no connection between our increased pace of life and the development of ADHD. If this theory were true, we would find that slower-paced societies have fewer cases of ADHD—but they don’t.
At most, we can say that ADHD symptoms are more obvious and debilitating in our fast-paced and complicated world. This is similar to saying that a white shirt is more obvious against a black background than it is against a white one, but we would never say that the black background caused the white shirt.
Natural Selection for a Different Time
Some people claim that those with ADHD are the descendants of hunters from our distant past, in contrast to the majority, who were farmers. The theory is that the quick reaction times and distractibility characteristic of ADHD actually were evolutionarily adaptive at one time.
By contrast, the farmers were better at routine and repetition. Unfortunately for these hunters, modern society no longer values those traits, so the hunters are forced to live in a farmer’s world.
These romanticized notions may make some people feel better about themselves in the moment (“Wow, I’m just a misunderstood hunter!”), but it doesn’t change the reality that people with ADHD need to function now in our current society, not in some inaccurate vision of life many thousands of years ago.
As I will repeat countless times in my books, I prefer to build people’s self-esteem by helping them change what they can, then accept the rest. This is easier if you start out with rock-solid information, because then no one can take that away from you by disproving your beliefs.
Neurology of ADHD
ADHD is a brain-based disorder. The brains of those with ADHD have been found to be different than the brains of those without ADHD in several ways. Most functions involve the interaction of more than one brain area, but the primary area affected by those with
ADHD is the frontal lobes. This is the area right behind the forehead. It is involved in some of the highest-level information processing, including the executive functions, which are discussed in other parts of the book.
Research has found that the affected areas are less active in those with ADHD compared with those without ADHD, at least when you take groups of people. (However, this doesn’t mean that brain scans can be used to diagnose individuals.) So because these parts of the brain don’t operate as effectively, folks with ADHD don’t process information as well in certain ways.
Our brains use dozens of different compounds as neurotransmitters, which serve as the signal between nerve cells and allow them to communicate. In ADHD, the affected areas use mostly dopamine, although some use norepinephrine.
The medications used to treat ADHD increase the amount of these neurotransmitters and thereby correct the shortfall. This also explains why the antidepressants, which mostly affect serotonin, have no direct benefit for ADHD, whereas the couple antidepressants that also affect norepinephrine have some potential benefit for ADHD.
Unfortunately, at this time, there is no way to reliably predict which medication will work best for which person without using trial and error. Interestingly, medication tends to make the brain scans of people with ADHD look more like those of people without ADHD, which makes sense, since it does the same to their performance.
Promoting Brain Health
Anything that is generally good for our brains is probably good for people with ADHD. I’m referring to the obvious things like eating a fully balanced diet, getting enough sleep, and exercising regularly.
The opposite can be said for the things that are generally bad for our brains and are best avoided, like cigarettes, alcohol, drugs, sedentary lifestyles, unhealthy foods, various toxins, and excessive stress.
However, the fact that these things affect our brains doesn’t mean that we consider them as part of the cause of ADHD—or use them as a central part of the treatment. Adding in more of the positives and minimizing the negatives will allow someone with ADHD to perform at her best but won’t change the fact that she still has ADHD.
By contrast, not doing enough of the good things and doing lots of the bad will only make the ADHD person perform worse. This is true for everyone, so it isn’t really an ADHD-specific intervention. So those New Year’s resolutions resolutions are good for all of us. Of course, sticking with them is easier said than done.
About the Author
*Ari Tuckman, PsyD, MBA, is a psychologist specializing in the diagnosis and treatment of ADHD in children and adults. He practices in West Chester, PA. A frequent presenter, he does everything from parent-teacher association meetings to teleclasses to full day continuing education seminars and likes all of them for different reasons. He does the popular podcast More Attention, Less Deficit for adults with ADHD that has 100 episodes and over 1,250,000 downloads.
Ari is the author of three critically-acclaimed books: Understand Your Brain, Get More Done: The ADHD Executive Functions Workbook, More Attention, Less Deficit: Success Strategies for Adults with ADHD, and Integrative Treatment for Adult ADHD: A Practical, Easy-to-Use Guide for Clinicians.
Ari has appeared on CNN, National Public Radio (NPR), and XM Radio and been quoted in The New York Times, Washington Post and Boston Globe.
ADDR Reviewed 8-22-2015 (mm)