Brain Imaging Reveals ADHD as a Collection of Different Disorders

Summary: A new study sheds light on ADHD, reporting teens with the disorder fit into one of three specific subgroups with distinct brain impairments and no common abnormalities between them.

Source: Elsevier.

Researchers have found that patients with different types of attention-deficit/hyperactivity disorder (ADHD) have impairments in unique brain systems, indicating that there may not be a one-size-fits-all explanation for the cause of the disorder. Based on performance on behavioral tests, adolescents with ADHD fit into one of three subgroups, where each group demonstrated distinct impairments in the brain with no common abnormalities between them.

The study, published in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, has the potential to radically reframe how researchers think about ADHD. “This study found evidence that clearly supports the idea that ADHD-diagnosed adolescents are not all the same neurobiologically,” said first author Dr. Michael Stevens, of the Olin Neuropsychiatry Research Center, Hartford, CT, and Yale University. Rather than a single disorder with small variations, the findings suggest that the diagnosis instead encompasses a “constellation” of different types of ADHD in which the brain functions in completely different ways.

The researchers tested 117 adolescents with ADHD to assess different types of impulsive behavior – a typical feature of ADHD. Three distinct groups emerged based on the participants’ performance. One group demonstrated impulsive motor responses during fast-moving visual tasks (a measure of executive function), one group showed a preference for immediate reward, and the third group performed relatively normal on both tasks, compared to 134 non-ADHD adolescents.

“These three ADHD subgroups were otherwise clinically indistinguishable for the most part,” said Dr. Stevens. “Without the specialized cognitive testing, a clinician would have had no way to tell apart the ADHD patients in one subgroup versus another.” Dr. Stevens and colleagues then used functional magnetic resonance imaging (fMRI), a technique that allows researchers to make connections between behavior and brain function, to investigate how these different impulsivity-related test profiles related to brain dysfunction.

“Far from having a core ADHD profile of brain dysfunction, there was not a single fMRI-measured abnormality that could be found in all three ADHD subgroups,” said Dr. Stevens. Instead, each subgroup had dysfunction in different brain regions related to their specific type of behavioral impairment.

“The results of this study highlight that there are different neural systems related to executive functions and reward processing that may contribute independently to the development of ADHD symptoms,” said Dr. Cameron Carter, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging.

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It will take more research to prove that ADHD is a collection of different disorders, but this study provides a big step in that direction. NeuroscienceNews.com image is in the public domain.

It will take more research to prove that ADHD is a collection of different disorders, but this study provides a big step in that direction. “Ultimately, by being open to the idea that psychiatric disorders like ADHD might be caused by more than one factor, it might be possible to advance our understanding of causes and treatments more rapidly,” said Dr. Stevens.

According to Dr. Carter, the findings suggest that future approaches using clinical assessments to identify the specific type of brain dysfunction contributing to a patient’s symptoms may allow a more targeted approach to treatment. For example, medications that may not appear to work well in a group of ADHD patients as a whole, may be effective for one particular subgroup that arises from a specific causal pathway.

About this neuroscience research article

Source: Elsevier
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Functional Neuroimaging Evidence for Distinct Neurobiological Pathways in Attention-Deficit/Hyperactivity Disorder” by Michael C. Stevens, Godfrey D. Pearlson, Vince D. Calhoun, Katie L. Bessette in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. Published online September 22 2017 doi:10.1016/j.bpsc.2017.09.005

Cite This NeuroscienceNews.com Article

[cbtabs][cbtab title=”MLA”]Elsevier “Brain Imaging Reveals ADHD as a Collection of Different Disorders.” NeuroscienceNews. NeuroscienceNews, 7 November 2017.
<https://neurosciencenews.com/adhd-spectrum-neuroimaging-7893/>.[/cbtab][cbtab title=”APA”]Elsevier (2017, November 7). Brain Imaging Reveals ADHD as a Collection of Different Disorders. NeuroscienceNews. Retrieved November 7, 2017 from https://neurosciencenews.com/adhd-spectrum-neuroimaging-7893/[/cbtab][cbtab title=”Chicago”]Elsevier “Brain Imaging Reveals ADHD as a Collection of Different Disorders.” https://neurosciencenews.com/adhd-spectrum-neuroimaging-7893/ (accessed November 7, 2017).[/cbtab][/cbtabs]


Abstract

Functional Neuroimaging Evidence for Distinct Neurobiological Pathways in Attention-Deficit/Hyperactivity Disorder

Background
A challenge facing clinical neuroscientists is how best to synthesize diverse and sometimes inconsistent evidence for neuropsychological deficits and brain system dysfunction found in psychiatric disorders into models that guide etiological and treatment research. Multiple-pathway models suggest that psychiatric symptoms might arise from pathophysiology in different neural systems. This study tested dual-pathway model predictions for attention-deficit/hyperactivity disorder (ADHD) that reward and executive function cognitive deficits should be related to abnormalities in corresponding functionally specialized neural systems.

Methods
Behavioral inhibition and preference for immediate rewards were assessed in N = 251 adolescent boys and girls ages 12 to 18 diagnosed with DSM-IV combined-subtype ADHD or non-ADHD control subjects. Following taxometric analyses of test performance, the resulting subgroups were compared on a functional magnetic resonance imaging monetary incentive delay task probing reward anticipation and go/no-go task of motor response inhibition.

Results
Three ADHD subgroups were identified consistent with different proposed pathways—ADHD with executive function/motor inhibition deficits, ADHD with both executive and reward deficits, and ADHD with relatively normal test performance. Each cognitive domain mapped to different ADHD brain dysfunction features as expected. However, no brain abnormalities were found common to all ADHD subgroups despite the fact they had nearly identical ADHD-related clinical characteristics.

Conclusions

The results suggest that combined-subtype ADHD is a collection of discrete disorders for which a comparable behavioral end point arises through different neurobiological pathways. The findings raise caution about applying common cause, single-deficit conceptual models to individual ADHD patients and should prompt researchers to consider biologically defined, multifactorial etiological models for other psychiatric diagnoses.

“Functional Neuroimaging Evidence for Distinct Neurobiological Pathways in Attention-Deficit/Hyperactivity Disorder” by Michael C. Stevens, Godfrey D. Pearlson, Vince D. Calhoun, Katie L. Bessette in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. Published online September 22 2017 doi:10.1016/j.bpsc.2017.09.005

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  1. So ADHD is something where just getting to know. I’m 37 and I was not diagnosed until I was in my late 20’s my brain does not work the same as others . To me it’s not a bad thing. But growing up I
    I’ve always been treated different cause I didn’t feel the same way or didn’t think the same way as others. This sucked. But knowing what I know now our Minds should be looked at as tools to making life and reasons to life’s as answers to questions great minds can’t answer. We see life different, live life different. Our brains have answered more questions than most brilliant minds can comprehend in a single sitting but know ok be will ever know cause they don’t ask but yet get shut down cause we’re different Stop looking at us as a burden but as a tool to help simply life for all….our minds our brilliant.

  2. My eldest daughter is ADHD and takes Straterra by choice, as it’s non-narcotic and works round the clock. We just realized in the last couple of years that she also has anxiety, but I believe struggling with the ADHD has actually made this worse than it maybe would have been. She has taken medication (Ritalin of some sort) in low doses since age 5 just to function in the world. Without it her life is chaos. Getting doctors to work with her through the years has been difficult to say the least. She’s done therapy many times and feels they help her none what so ever. She says they all just ask questions wanting her to produce answers and never suggest she try anything different. The latest group practice she has been utilizing makes her miss work to come in monthly just to get her medication refilled and it’s non-narcotic. The last newbie Dr. had the audacity to tell her that Straterra wasn’t designed to be taken long term, yet they told her four years ago, that it was safe enough to take through her pregnancy. Which she chose not to do, just in case they were wrong. This Dr. insinuated that she more or less should have “outgrown” being ADHD! Like a magic switch gets flipped in your brain, when you grow up? Poof, you’re cured? How crazy scary is that type of thinking? Mental health care has taken a big back slide in the last 25-50 years and it’s more prevalent that anyone even realizes. My daughter’s life just doesn’t work without the medication and we both know this. She can’t stay on task, has a short fuse and generally gets nothing accomplished to completion. Even her boss can tell when she hasn’t taken her medication. Now we are going through the same thing with her eldest daughter who’s been diagnosed as ADHD as well. The difference between low dose and no medication with her is remarkable as well. Parents know the difference. My girls are not drugged out and laying around, they’re just able to function better, less chaotically. Someday they’ll actually have more definitive answers than this study. We already knew no two ADHD people are exactly alike. Though my daughter and granddaughter seem to be genetically on the same wrung of this three step ladder called ADHD.

  3. These results only confirm my very strong opinion that ADHD is extremely overdiagnosed, and that many children who are diagnosed are simply undisciplined or immature. This does a disservice to those who truly ARE ADHD in the most clinical and neurological sense- like my SON- who can never get the help and understanding he needs because teachers and administrators expect him to behave like these other “ADHD” kids, who are fully capable of NOT “being ADHD” if they have sufficient motivation. Preference for immediate reward= not made to practice self-denial on a regular basis. And performing normally? Likely the ones who act out because they want attention, not because they are TRULY ADHD. STOP OVERDIAGNOSING! Let the kids who TRULY have the disorder get the help they need! Be willing to tell parents that their child is not sick, he is just in need of discipline!

    1. It’s ironic that you would be so judgmental about other people whose suffering is “different” than your son’s, considering what you have been through. As an adult who was diagnosed with ADD, getting on the right medication has changed my life. After decades of misdiagnosis and being shoved onto antidepressants, when I kept telling them I was NOT depressed, my brain just felt different than others, I finally found a psych who saw the issue and helped me. If anything, I think ADD is under-diagnosed. I also believe that much like autism, it is a spectrum disorder and not a “one size fits all.” Oh, and I assure you, as someone who grew up in the 70’s, lack of discipline was NOT my problem. Best wishes.

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