Updates on ADHD Research: Epigenetics, Brain Training, and Neuroimaging

A substantial body of research over the years has found that ADHD is characterized by high heritability and involves many different genes, has replicable findings in neuroimaging studies, has effective treatments (both non-pharmacologic and pharmacologic), and is associated with adverse long-term outcomes. Yet many questions remain unanswered.

While no one can predict the scientific discoveries that lie ahead, three research areas are especially promising for improving our understanding of ADHD: neuroimaging, genetic research, and non-pharmacologic interventions, like transcranial magnetic stimulation and attention training.

Advances in brain-imaging techniques may lead to a better understanding of the neural mechanisms underlying ADHD. There are caveats, however. It appears that single neuroimaging receptor or cellular studies have provided clues about differences in brain structure and functioning in individuals with ADHD, but the brain comprises billions of interacting cells, circuits, and networks that do or do not work together during specific tasks.

These complex networks and connections vary by individual and by the specific tasks that are part of many neuroimaging studies. Researchers are asking:

Slowly, the field is moving away from static representations of cellular or receptor activities in specific brain regions and looking instead at how the whole brain (rather than the simple sum of its single parts) functions. Neuroimaging tools (i.e., Brain SPECT, PET and CAT scans, and fMRI) cannot yet make an accurate diagnosis of ADHD, but we’ll look for important breakthroughs in this area.

Further exploration of genetic factors could shed light on the heritability of ADHD and pave the way for targeted therapies based on an individual’s genetic profile. While the study of genetic factors has provided important clues, we now know that there is no single gene or small set of genes that reliably predict whether someone will have ADHD. Moreover, the specific genes that put one individual at risk for ADHD may differ from those found in another person with ADHD.

This is where epigenetic research comes into play. Researchers are asking:

As we discover more specific gene and brain developmental pathways, we should expect to find that different and precise interventions work for different ADHD subtypes, depending on the individual’s particular gene-environment mix and how factors unfold over time.

Cognitive-behavioral therapies, neurofeedback, and computerized attention training programs have expanded our treatment options beyond medication.

Technologies using video game formats to provide specific brain exercises may lead to potential attentional benefits, presumably by strengthening specific brain circuits. Examples of brain training programs include EndeavorRX, Joon, Mightier, and Calmsie.

Neurostimulation devices offer new techniques for managing ADHD symptoms more effectively. Examples include the Monarch eTNS system, which uses an external wearable device that stimulates the Vagus nerve, as well as devices that deliver transcranial magnetic stimulation (TMS) to the brain through an externally applied device. While TMS has been approved for depression, anxiety, and obsessive-compulsive disorder, it has been studied but not yet approved for ADHD.

These new interventions are exciting; however, we do not have sufficient research data comparing the efficacy of any of these treatments with more established and efficacious pharmacologic interventions and cognitive behavior therapies.