ADHD: From a Neurologist and a Mom’s Perspective
I treat ADD/ADHD. Throughout this website ADHD will be used for inattentive and hyperactive types. I see parents come into the office and say they don’t want their kids on stimulants, but they want me to do something to fix the problem. The younger kid is running around too much, the older kid is disrespectful, can’t focus in class, has low grades, can’t finish homework or focus.
I can give stimulants or non-stimulant ADHD medications. But none of these medications fix the problem the parents originally came in for. They may miss the point of the visit, the parents are not satisfied, the kid feels blamed for not focusing well enough in school, over-medicated. Often the kids resent their medications, don’t want to take their medications, especially the pre-teens and teens. The kids may be bright.
People ask me all the time about alternatives. Do they work? Does staying away from sugar, milk, wheat, tomatoes, etc. make any difference or are these diets a waste of time? We don’t know the full answers yet—that’s what has to be admitted. We do not have reams of research that can answer these questions with certainty. Maybe they work for some small subset of kids—but how do we as physicians pick out the kids who would benefit from diet changes? We don’t know and won’t know if the research money never goes to this kind of study.
What about better parenting? Stricter parenting? Therapy? Does that work? We don’t have all the research I need to advise parents. This is the evidence on ADHD so far.
NIMH Multimodal Treatment of Children with ADHD (MTA) Study
The most famous study is by Peter S. Jensen (JAACAP, 2007), the Multimodal Treatment Study of Children with Attention Deficit Hyperactivity Disorder, a large study of 579 kids ages 10–13. It compared four approaches: behavior therapy, medication, therapy plus medications, routine community care.
Medications at first year seemed to be more effective, but the surprise result was this: at 3 years, the medications were no longer superior to the other 3 methods in treating ADHD. At 3 year follow up, many kids were not taking their medications, only 45–71% of kids were taking medications. He concluded that the “ones taking medications were not better than the others” (Peter S. Jensen, CNS Spectrums, 2005). The research also found that patients with combined psychotherapy plus medications were able to lower the amount of medications. This shows that ADHD is not only treatable by blocking dopamine reuptake with stimulants, but also is treatable by some change, chemical or otherwise, that occurs as a result of talking with a therapist. But we don’t yet know which therapy is the most effective.
What about articles that ADHD kids are geniuses in disguise? Is that true? This is so attractive partially because we’re moms and want to be proud, but also because so many moms feel that school and doctors are not seeing the potential we see. We see too little attention being paid to developing the positive parts of our kids that we can see shine through at different times. We have no strategy to build on positives for ADHD kids in school or with medication.
We neurologists don’t know the full answers to the most frequently asked questions that parents ask me. We have to admit we don’t know. This is written to bring you up to date on what we neurologists do know as of April 2010. Understanding the result of ADHD research so far will help you to make better decisions as a parent of an ADHD kid or as an adult ADHD person.
FAQs from Parents and Patients with ADHD
Did my child inherit this from me or my spouse?
If one person has ADHD, there is a 25–35% probability that another family member has ADHD. About 25% of ADHD kids, or one in 4, have other members of the family with ADHD. ADD patients have been identified in every country studied, and with approximately the same percentages.
A study of twins found that 90% of kids with a diagnosis of ADHD had a twin with the same diagnosis. ADHD is among the most inherited psychological disorders. The mean heritability is 76% as per Stephen Faraone (Biol. Psychiatry, 2005).
What is known about the ADHD genes?
There are several genes that may increase risk of ADHD. Neuroscientists are very interested in the genes that encode the proteins for the dopamine transporter molecule and the norepinephrine transporter molecule as per Dr. Kim (PNAA, 2006). One of the genes found to be part of ADHD is coding for novelty seeking and extraversion. It is named dopamine D4/dopamine 4 receptor subtype (DRD4) receptor gene.
Will my child have the disorder as an adult?
Studies on this differ widely in their answers—approximately 30–80% of kids with ADHD still have the disorder as adults.
Is the ADHD brain formed differently or abnormally?
Brain differences between ADHD kids and others in volume and chemistry have been found.
How is brain volume different for ADHD patients?
A 10 year study by NIMH demonstrated that the brains of kids with ADHD are 3–4% smaller than those of kids without ADHD. At first, scientists thought the low brain volume was due to medications, but those who never had medications also had the low brain volume.
Is brain chemistry different for ADHD people? Dopamine
We know that methylphenidate (Ritalin) works by increasing the dopamine in the brain synapses between two neurons by blocking dopamine re-uptake (it blocks the dopamine transporters). Volkow (J Neurosci, 2001) studied ADHD patients before and after taking methylphenidate with PET scanning.
A research study using D2 receptor radioligand that competes with endogenous dopamine for binding to the receptor to evaluate whether methylphenidate changes extracellular dopamine in 11 controls concluded that methylphenidate significantly increases extracellular dopamine in the human brain.
Do ADHD patients make enough dopamine?
Adults with ADHD had abnormally low levels of DOPA decarboxylase, the enzyme that produces dopamine. Research by Ernst (Journal of Neurosci, 1998), using PET imaging, found that adults with ADHD had abnormally low dopa decarboxylase activity in the prefrontal cortex.
Why do stimulants increase dopamine in the brain?
Stimulants increase dopamine for two reasons: dopamine increases the ability to distinguish important things from background noise, strengthening weak dopamine signals in ADHD kids and enhancing attention while decreasing distractions from background noise. Dopamine is also a neurotransmitter involved with motivation and reward, so stimulants can increase goal-directed activities aimed at getting more rewards.
Research by Volkow (JAMA, 2009) described reward and motivation systems using dopamine in ADHD adults. Increased dopamine transporters have been found in ADHD patients, which could result in reduced extracellular dopamine. PET measurement of dopamine transporters and receptors found binding of dopamine was abnormally low in ADHD patients compared to non-ADHD controls in regions of the dopamine reward pathway.
Are other chemicals, besides dopamine, important in ADHD?
Norepinephrine, GABA, glucose are all important in ADHD. Research by Zametkin (NEJM, 1990 and Arch Gen Psych, 1993) found that teens and adults with past or current history of ADHD on continuous performance tests had 8.1% lower levels of cerebral glucose metabolism than non-ADHD people, with the main differences in superior prefrontal cortex and premotor areas.
Nucleus accumbens, a small collection of neurons in the lower front part of the brain, releases GABA, an inhibitory neurotransmitter that inhibits actions of the brain. Nucleus accumbens is controlled by dopamine released from the VTA/ventral tegmental area also in the lower frontal area of the brain.
Why do some medications for ADHD advertise that norepinephrine is the target, in addition to dopamine?
We need norepinephrine in the prefrontal cortex to control our impulsivity. Arnstein (Arch Gen Psych, 1996) studied dysfunction of the norepinephrine receptor in the prefrontal cortex and reported that this deficiency is part of the problem causing lack of inhibition in patients with ADHD.
What are differences in brain metabolism?
Brain areas that help us to dampen impulsiveness, and control our speech and movements (caudate and putamen) have been found to be under-active. Research by Vaidya (Am J Psych, 2005) using functional MRI indicates that the frontal lobes and striatal regions have reduced metabolism in boys with ADHD. Boys with ADHD were not able to fully activate the caudate nucleus. Methylphenidate enhances activity of these hypoactive regions in boys with ADHD, but not healthy boys in Vaidya’s research.
What other diseases can cause ADHD symptoms so should be ruled out by the physician?
We know that thyroid disorders, sleep disorders, infectious diseases (e.g. HIV), anxiety, neurofibromatosis, lead poisoning, and central nervous system toxins can cause ADHD symptoms. Testing can include an EEG, HIV testing, Lyme testing, lead testing, genetic testing, sleep study, thyroid testing, psychosocial stressors, and evaluation of cognition and memory.
Can anything in pregnancy lead to ADHD?
Exposure to PCBs in the pregnant mother or exposure to lead in the young toddler’s brain can lead to ADHD symptoms.
Does sugar increase hyperactivity?
Feingold (Why Your Child is Hyperactive, 1975) did research on ADD and concluded that sugar causes hyperactivity. Other scientists disagreed strongly with his research. However, many parents who come into the office report that when they keep their children away from sugar, they are much less hyperactive. We do not have the definitive amount of research on this that would make me feel certain either for or against Feingold’s research.