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Reframing ADHD in the Genomic Era: Page 2 of 2

Reframing ADHD in the Genomic Era: Page 2 of 2

Table

Potential strengths in ADHD

The neurobiological research in ADHD suggests several neural systems that may contribute to putative strengths. For example, the atypical right/left cerebral asymmetries and a right hemisphere "bias" observed in ADHD30 may contribute to insight problem solving,31,32 intuition, or creativity,33,34 as well as self-transcendence (a character component of personality).35 Adults with ADHD have been shown to score more highly on measures of self-transcendence,36 a trait associated with improved survival after illness or end-of-life stages,37 although this finding requires replication. Novelty-seeking, a temperament trait, is associated with ADHD,36 and this construct may be associated with creativity and innovation,38 while daydreaming (a common behavioral feature of ADHD) may be associated with creativity and learning.35,39

These traits (daydreaming, creativity, intuition, self-transcendence) require more rigorous research because they may reflect strengths of neurobiological continua associated with ADHD that may be enhanced in certain environmental settings. Further work is warranted to elucidate the relative influence of these continua with ADHD and how recognition and enhancement of these traits may serve to improve the quality of life and minimize impairment associated with ADHD.

A neurodiversity framework

Reframing ADHD as an atypical mode of neural functioning often associated with impairment takes it out of a categorical diagnosis of a medical disorder into a neurodiversity framework that highlights the relationship of our genomes to our brains and behavior and sets the foundation for change in how we, as a community, view ADHD.

This reconceptualization of ADHD as a trait does not minimize that it can be and often is "impairing" and that individuals who have ADHD may need professional help. However, it places a more significant burden of responsibility for reducing impairment within the context of the community and social networks in which the child is raised or the adult lives.

Empirical data support the strong role that family environmental stress can have on the impairment associated with ADHD but not necessarily on the development of the trait per se.40 Reframing ADHD within the context of a neurodiversity model may shift some of the responsibility of change onto the social settings in which children are raised (school systems, family systems, health care systems) rather than the child. Specifically, providing education and discussion as a community of ADHD as an extreme on a normal continuum is important for destigmatizing the diagnosis. This approach may, in and of itself, help reduce impairment in ADHD and reduce comorbid psychiatric sequelae (low self-esteem, depression, substance abuse) because the environment within which the child, adolescent, or adult functions may be less shame-inducing and more embracing of diversity.

Recognizing the nature of impairment

The relative nature of impairment must be recognized and discussed to highlight the individual child's strengths and difficulties and to design the best programs for fostering growth of strengths and management of difficulties. The increased prevalence of ADHD over the past several decades reflects a broadening definition of a disorder, in part, because impairment is evident in a greater proportion of individuals at the extremes of population continua. This shift is, in part, due to the recognition of impairment associated with inattentive symptoms, with few or no symptoms of hyperactivity-impulsivity (ie, the inattentive subtype). The expansion of ADHD classification may reflect the increasing cultural focus on and perceived value of what might be considered simplis-tically left hemisphere, language-based, product-oriented behavior (ie, "doing") at the expense of possibly more right hemisphere–oriented activities—nonlinear, nonlanguage-based, creative, intuitive processes (ie, "being.").

The current emphasis on the former in our schools and workplaces, at the expense of the latter, is fostering greater impairment (ie, stress) at the population level in general, and particularly for those who are inherently more oriented toward "being." Most important, we need to address at a cultural level what we deem important in education, perhaps increasing the value we place on creativity, reflection, and awareness practices, to balance the emphasis on doing and producing.

Individualized treatment

Individualized medicine will become of greater importance as specific gene patterns are identified that respond differently to pharmaceutical interventions. Even with improved community, family, and self-regulatory tools (discussed below), there will be children/adults along continua associated with ADHD in whom pharmaceutical intervention will be most beneficial to manage or minimize impairment.

In the future, DNA-based diagnostics will allow more carefully designed drug interventions that target specific biochemical profiles. Ongoing pharmacogenomic studies are beginning to investigate drug efficacy as a function of specific gene variants that may lead to increased improvement or more individually tailored treatments. Yet, as of today, there are no genes sufficiently validated or specific enough to warrant their use in clinical practice.

Prevention

Intervention for the most part will shift to prevention of impairment. It is clear from emerging work in gene expression that genetic does not mean fixed. While we are born with a genetic blueprint, the diversity of gene expression stemming from that blueprint is largely a function of environmental influences. The 21st century will likely yield radically new insights into a range of diversity based on gene regulation and what we as parents, clinicians, and individuals can do to modify gene expression.

While psychosocial and behavioral interventions have yet to be shown to be strong factors in ADHD treatment, they may prove to be extremely valuable—perhaps in a cumulative way—for promoting resiliency and prevention of impairment if initiated early. There is a need to invest in more research of behavioral tools that are likely to be more conducive to prevention than pharmaceutical interventions, since taking medications before the onset of symptoms is highly unlikely.

Self-regulatory practices, such as exercise, attention and memory training, meditation, and biofeedback, may provide small but positive effects on particular brain and body networks involved in ADHD.41-43 Perhaps, just as diet and exercise promote a healthy heart, multiple behavioral changes will be necessary to promote emotional and learning well-being. Furthermore, as with dyslexia, the earlier the introduction of behavioral tools, the better the outcome.44 These behavioral tools may help children and adults with ADHD learn to self-regulate. There is a need for extensive and rigorous research in this area.

One area of increasing interest is the role of "self-regulatory" tools in biological and brain change. Biofeedback, neurofeedback, meditation, and brain-training tools may prove more beneficial to neural regulation (and self-regulation of gene expression) as we move from intervention to prevention. Exciting research on such mechanisms with neural circuits underlying attention, memory, and emotional regulation has emerged in the past decade, suggesting that this is an important area of research in ADHD.45-48 Our laboratory recently applied a mindfulness meditation program in a small, uncontrolled study in adults and teens and found beneficial effects,49 and research on neural structures and networks underlying attention have shown that mindfulness meditation does lead to significant cognitive brain changes in non-ADHD populations.50,51 These sorts of studies, while intriguing, require large database study, because other small studies of alternative approaches have not—in large study designs—proved to be effective.52 It is imperative, nevertheless, that research begins to target more programs that may be easily translated into impairment prevention models that maximize strengths, as genetic risk detection becomes possible. Basic research investigating the mechanisms of action of such tools is needed to provide the scientific rational for their application in ADHD.

Limitations of the model

Notwithstanding the advantages of a neurodiversity model, there are potential pitfalls with this conceptual framework. First and foremost is the impact such a model might have on treatment services. Under a medical model, ADHD is recognized as a disorder that warrants medical attention. The absence of such a framework might make access to services more limited instead of creating increased attention and access to resources by a broader range of individuals, families, and programmatic services. Introducing quantitative criteria into the diagnostic classification of ADHD1 may be a first step in a transition from categorical "medical model" classification to a more hybrid approach (continuous and categorical) that better reflects the continuous nature of the underlying condition.

Second, interpretation of ADHD as a variant along continua may be misinterpreted as implying that there is a single underlying genetically mediated continuum accounting for ADHD. This is definitely not the case, as is reflected by both molecular and neuropsychological research to date. As with other complex traits—such as heart disease—there are likely to be multiple genes influencing ADHD liability—genes that contribute to emotional regulation, attention, right/left hemisphere asymmetry, or temperament—all of which may be expected to vary in intensity across individuals with ADHD. Heterogeneity will likely be the norm, and as genes are uncovered that contribute to ADHD liability, they will differ in effect size from small to medium across individuals, families, and populations and also as a function of environment experience.

Conclusion and summary

Reframing ADHD in the genomic era means shifting our view of it as solely a medical disorder to viewing it as a complex and heritable trait composed of 1 or more continua of neural functioning in the population. Impairment arises as a function of the less common (atypical) nature of neural functioning and the subsequent difficulties arising within cultural or social norms. Different genes and environments contribute to these continua and vary across individuals and populations. Reframing ADHD from this perspective means:

  • A greater emphasis toward treatment and prevention in the social networks of the child or adult.
  • Increased research on strengths associated with ADHD as well as difficulties.
  • Individual treatment tailored toward high-risk genes.
  • The development of preventive modalities to reduce the impairment associated with atypical neural processing.

Hazards associated with a shift away from a medical model of ADHD include potential reduced services and misunderstanding of the heterogeneous nature of the condition. Inclusion of both continuous and categorical criteria for diagnoses may be a first step in recognizing the continuous nature of the disorder itself.

 

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References

References


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