Dopamine & ADHD

thinkingm4  The Journal of the American Medical Association (JAMA. 2009;302(10):1084-1091) recently published work by Dr. Nora D. Volkow, MD, et al regarding evaluation of the biological bases that may reveal a reward/motivational deficit present in the brains of persons with ADHD.

Volkow and her colleagues theorized that ADHD may be connected to reward-motivation deficits. Volkow investigated whether lack of motivation and its relationship to reward could be traced to depression of dopamine in various areas of the brain.

To determine whether dopamine was depressed in ADHD persons, the researchers used positron emission tomography (PET scans) to measure dopamine levels in 53 nonmedicated ADHD adults and 44 healthy non ADHD adults between 2001-2009.

Since the biological mechanisms of ADHD are unknown, studies of this type have become the holy grails of research. While Volkow’s credentials are quite impressive (NIH, NIDA, etc.) this research is not new or conclusive. The theory that dopamine dysfunction/depression may be involved with ADHD symptoms has been researched for many years.

Furthermore, Volkow’s  small sample size consisted only of adults and therefore should not be extrapolated to include the child population. The small sample size alone should prevent it from being generalized to the entire adult ADHD population. One has a problem of antecedence here; is ADHD caused by dopamine depression in the brain? Or is the dopamine depression the result of ADHD that was acquired by other biological means? This research cannot answer that question.

What does the research tell us? It tells us that for some adults, dopamine may play a role in ADHD. For those adults, taking a stimulant medication may increase dopaminergic activity thus increasing reward/motivation responses and thus increasing attention to task. That might be a stretch.

On the downside, persons with depressed dopamine levels would probably greatly enjoy using stimulants. Study participants reported this. This may contribute to the frequent incidences of substance abuse among ADHD persons.

The authors write,"Despite decades of research, the specific neurobiological mechanisms underlying this disorder still remain unclear. Genetic, clinical and imaging studies point to a disruption of the brain dopamine system, which is corroborated by the clinical effectiveness of stimulant drugs (methylphenidate hydrochloride and amphetamine), which increase extracellular dopamine in the brain."

Unfortunately, the study leaves us with more questions than answers. Does it tell us what happens long term? Does it tell us of side effects?  Does it tell us if this actually applies to children? Can we conclusively determine a causal relationship between reward/motivation and ADHD? Does it solve the problem of antecedence? Do we know anything conclusively about all ADHD adults. No. There’s still a long road ahead.

Youth and Video Game Addiction

The journal, Psychological Science (May, 2009 Douglas Gentile. Pathological Video Game Use among Youth 8 to 18: A National Study) sampled youth aged 8 to 18.

Iowa State University Assistant Professor of Psychology, Douglas Gentile, found that 8.5% of the gamers to be pathological players. Gentile bases his statistics on standards established for pathological gambling. So, while parents often cite that their child is ‘addicted’ to video games, Gentile’s standards necessitated that video game play actually caused family, social, school or psychological damage due to video game playing habits.

“What we mean by pathological use is that something someone is doing – in this case, playing video games – is damaging to their functioning,” Gentile said. “It’s not simply doing it a lot. It has to harm functioning in multiple ways.”

On average, the pathological gamers in the study played video games at least 24 hours per week. This is nearly twice as much as non-pathological gamers. Parents of pathological gamers also allowed their children to have video game systems in their bedrooms far more often than non-pathological gamers. 

According to Science Daily, Gentile found that pathological gamers reported having more trouble paying attention in school and thus received poorer grades in school, had more health problems, were more likely to feel “addicted,” and even stole to support their habit.

The study also found that pathological gamers were twice as likely to have been diagnosed with attention problems such as Attention Deficit Disorder or Attention Deficit Hyperactivity Disorder.

“There is still much we do not know,” Gentile said. “We don’t know who’s most at risk, or whether this is part of a pattern of disorders. That’s important because many disorders are co-morbid with others. It may be a symptom of depression, for example. And so we would want to understand that pattern of co-morbidity because that would help us know how to treat it.”

Gentile is continuing his own research, currently conducting both longitudinal and clinical studies to determine risk factors and symptoms found in pathological youth gamers.

It is wise for parents to limit use of video games and TV. Treat them as you would dessert; limited portions used as a reward.

ADHD Prescription Drug Abuse

A study published in the journal Pediatrics reports that teenage abuse of drugs prescribed for ADHD increased 76 percent from 1998 to 2005. The study was based on calls to poison control centers across the nation. Effects from this abuse can be agitation, rapid heart beat, and dangerously blood pressure.

Many teens and college age students know that taking ADHD medication results in the same effect for persons who do not have attention problems. Low dose stimulant medication increases focus and one’s ability to stay attentive to boring tasks. It has become the drug of choice for studying for exams.