Does ADHD Really Exist?

Does ADHD Really Exist?

People who have ADHD know ADHD does really exist, and is real and there are real problems with living with ADHD and it’s not a conspiracy of big pharma, the unicorn hordes colluding with the space aliens and the reptile people, but sadly some still do not know this.

And they stigmatize children and adults with ADHD, and try to shame both for treating ADHD with one of the many ways to manage ADHD, with ADHD medications, which have been used for 70+ years and have hundreds if not thousands of peer reviewed research articles on them.

“Don’t drug our kids! they demand” then later they ask “hey why are so many people who say they have ADHD addicted to illegal drugs and alcohol?”

And just like it seems that many of the “family values” crowd who hate they gays so much often seem to be outed as closet case gays, it often seems many of the ADHD stigmatizers also seem to be ADHD closet cases too.

Why is this a problem?

Sample Response to a Person with a General Lack of Knowledge of ADHD

Sample Response to a Person Who’s Strongly Denying ADHD Exists

Clinical Evidence of The Existence of ADHD as a Real Condition

Why is this a problem?

Occasionally I read about people who claim that ADHD doesn’t exist. As if you cut down on sugar intake, turn off TV and computer games, and spin around 3 times and click your heels it will magically disappear.

Well, that is not true. For the people who have to deal with the challenges of ADHD, especially adults, who often have few resources available to them, this is like kicking someone when they’re down.

Many people with ADHD don’t seek a proper diagnosis of ADHD or learn the different ways to manage ADHD for themselves or their children because of the ADHD stigma created by some judgemental ignorant people.

Would you tell someone who’s a diabetic that he shouldn’t take insulin, it’s not good for them, diabetes is a phoney condition thought up by the drug companies and all they have to do is stay away from the chocolate bars and have happy thoughts?

Why is it that people who would not assume they’re knowledgeable enough to make pronouncements of the validity of physical medical conditions assume that they are knowledgeable enough to make sweeping pronouncements of the validity of mental medical conditions?

Why do they then decide (usually without doing any real research on the subject) that they know enough about what are acceptable and unacceptable treatments ( i.e., Ritalin as a tool of the devil theory) and condemn someone for using what they deem are unacceptable treatments? As if the brain is easier to understand than the body.

ADHD Stigma and The ADHD Catch 22.

My article for Transitions Magazine the quarterly for The Disability Alliance of BC ( used to be called BC Coalition of People with Disabilities (BCCPD) in their issue focusing on stigma. Covers ADHD myths and how to deal with people who stigmatize ADDers.

While ADD is sometimes underdiagnosed, overdiagnosed and misdiagnosed, most commonly UNDERdiagnosed, it is a real condition with often severe negative consequences for the person who has it.

Once they learn about the condition and begin to deal with it, by medication, coaching, therapy, support groups or other methods. Then they can start focusing on and developing the advantages of having ADHD.

Unfortunately, too many people with ADD don’t even get diagnosed because of the misinformation and stigma out there by the ignorant (occasionally vocally ignorant). You can’t deal with what you don’t know you have.

So as an Adult ADHD Coach who has ADHD, and self medicates with information and learning, I’ve put together a few links to articles that give hard, clinical evidence of the existence of ADHD as a real condition.

If you have ADHD, how you decide to treat it should be your choice not something that is dictated by others. After all you’re the one who has to deal with the consequences of your choices (or of simply continually researching the condition with little action).

Sample Response to a Person with a General Lack of Knowledge of ADHD

If someone simply has a lack of knowledge about ADHD, or believes the myths out there, you can give them this blood pressure analogy to explain it.

“We all have blood pressure. If it’s in x range it’s normal, if it’s in y range it’s a cause for concern, and if it’s in z range you have a medical condition called hypertension and have to be treated for it.”

You could use a similar example with blood sugar levels. I.e., occasionally low blood sugar, hypoglycemia and diabetes.

You could also use the example of clinical depression. Some people have some of the symptoms of depression on occasion i.e., they may feel sad and depressed for a single day but that does not make them clinically depressed. You need to have a certain number of symptoms over a certain period of time and a certain degree of severity.

Most people have some of the symptoms of ADHD on occasion, but just becasues you’re sad for a weekend, that doesn’t make you clinically depressed. What makes it ADHD is:

• How many of the symptoms you have
• How severe the symptoms are
• The degree that they negatively effect one or more areas of your life
• How long they have been a problem in your life.

Sample Response to a Person Who’s Strongly Denying ADHD Exists

If that doesn’t work and you’re dealing with someone who is strongly denying that ADHD exists and claiming that ADHD is a not real condition, thereby stigmatizing those with ADHD and preventing other people who may have undiagnosed ADD from seeking treatment, you might consider asking them this question,

“What do you know about ADHD that the following institutions don’t?

American Medical Association (AMA)
Canadian Medical Association
Canadian Psychological Association
Canadian Psychiatric Association
Surgeon General of the United States
National Institutes of Health (NIH)
Centers for Disease Control and Prevention (CDC)
American Academy of Pediatrics (AAP)
American Academy of Child and Adolescent Psychiatry (AACAP)
(See the bottom of this page for more details Real Science Defines AD/HD as a Real Disorder).

They all say ADHD exists and is a real condition.

What research have you done that show’s that all of the organizations above are wrong?” And “where did you get your medical degree?”

Clinical Evidence of The Existence of ADHD as a Real Condition

Altered Neural Substrates of Cognitive Control in Childhood ADHD: Evidence From Functional Magnetic Resonance Imaging

“Objective

The study compared the neural bases of two cognitive control operations, interference suppression and response inhibition, between children with and children without attention deficit hyperactivity disorder (ADHD).

Method

Ten children (7–11 years of age) with combined-type ADHD and 10 comparison subjects matched for age and gender underwent rapid event-related functional magnetic resonance imaging (fMRI) during performance of a modified flanker task.

Functional maps were generated through group averaging and performance-based correlational analyses.

Results

Interference suppression in ADHD subjects was characterized by reduced engagement of a frontal-striatal-temporal-parietal network that subserved healthy performance.

In contrast, response inhibition performance relied upon different regions in the two groups, frontal-striatal in comparison subjects but right superior temporal in ADHD children.

Conclusions

Alteration in the neural basis of two cognitive control operations in childhood ADHD was characterized by distinct, rather than unitary, patterns of functional abnormality.

Greater between-group overlap in the neural network activated for interference suppression than in response inhibition suggests that components of cognitive control are differentially sensitive to ADHD.

The ADHD children’s inability to activate the caudate nucleus constitutes a core abnormality in ADHD. Observed functional abnormalities did not result from prolonged stimulant exposure, since most children were medication naive.”

A Review Of Fronto-Striatal And Fronto-Cortical Brain Abnormalities In Children And Adults With Attention Deficit Hyperactivity Disorder (ADHD) And New Evidence For Dysfunction In Adults With Adhd During Motivation And Attention

Cortex. “In this paper we review the current structural and functional imaging evidence for abnormalities in children and adults with ADHD in fronto-striatal, fronto-parieto-temporal, fronto-cerebellar and fronto-limbic regions and networks.

While the imaging studies in children with ADHD are more numerous and consistent, an increasing number of studies suggests that these structural and functional abnormalities in fronto-cortical and fronto-subcortical networks persist into adulthood, despite a relative symptomatic improvement in the adult form of the disorder.

We furthermore present new data that support the notion of a persistence of neurofunctional deficits in adults with ADHD during attention and motivation functions.

We show that a group of medication-naïve young adults with ADHD behaviours who were followed up 20 years from a childhood ADHD diagnosis show dysfunctions in lateral fronto-striato-parietal regions relative to controls during sustained attention, as well as in ventromedial orbitofrontal regions during reward, suggesting dysfunctions in cognitive-attentional as well as motivational neural networks.

The lateral fronto-striatal deficit findings, furthermore, were strikingly similar to those we have previously observed in children with ADHD during the same task, reinforcing the notion of persistence of fronto-striatal dysfunctions in adult ADHD.

The ventromedial orbitofrontal deficits, however, were associated with comorbid conduct disorder (CD), highlighting the potential confound of comorbid antisocial conditions on paralimbic brain deficits in ADHD.

Our review supported by the new data therefore suggest that both adult and childhood ADHD are associated with brain abnormalities in fronto-cortical and fronto-subcortical systems that mediate the control of cognition and motivation.

The brain deficits in ADHD therefore appear to be multi-systemic and to persist throughout the lifespan.”

ADHD Is Characterized By A Delay In Cortical Maturation

Proceedings of The National Academy of Sciences of the USA.

“We found maturation to progress in a similar manner regionally in both children with and without ADHD, with primary sensory areas attaining peak cortical thickness before polymodal, high-order association areas.

However, there was a marked delay in ADHD in attaining peak thickness throughout most of the cerebrum: the median age by which 50% of the cortical points attained peak thickness for this group was 10.5 years (SE 0.01), which was significantly later than the median age of 7.5 years (SE 0.02) for typically developing controls (log rank test χ(1)2 = 5,609, P < 1.0 × 10−20).

The delay was most prominent in prefrontal regions important for control of cognitive processes including attention and motor planning. Neuroanatomic documentation of a delay in regional cortical maturation in ADHD has not been previously reported.”
Supporting info and movies here.

ADHD: More Prevalent Than We Thought?

Larissa Hirsch, MD Instructor of pediatrics at New York Presbyterian Hospital, medical editor for KidsHealth.org and Charles A. Pohl, MD, professor of pediatrics and associate dean of student affairs and career counseling at Jefferson Medical College in Philadelphia

“There are frequently stories in the news and talk among the public of the over-diagnosis and treatment of attention deficit hyperactivity disorder (ADHD) in today’s hypervigilant society.

However, a study recently published in Archives of Pediatrics and Adolescent Medicine may serve to debunk this common belief…Interestingly, only 47.9% of the caregivers of children who met the DSM-IV criteria in the past year reported that the disorder had been diagnosed in their child…Children from the lowest income group received less consistent treatment than those in higher income groups.

The Froehlich study indicates that we are under-diagnosing ADHD. We need to be on the lookout for children with this disorder, make an accurate diagnosis, and do our best to follow affected children closely.”

Attention and Executive Systems Abnormalities In Adults With Childhood ADHD: A DT-MRI Study of Connections.

Cerebral Cortex. “In this study of adults with childhood ADHD, we hypothesized that fiber pathways subserving attention and executive functions (EFs) would be altered.

To this end, the cingulum bundle (CB) and superior longitudinal fascicle II (SLF II) were investigated in vivo in 12 adults with childhood ADHD and 17 demographically comparable unaffected controls using DT-MRI.

Relative to controls, the fractional anisotropy (FA) values were significantly smaller in both regions of interest in the right hemisphere, in contrast to a control region (the fornix), indicating an alteration of anatomical connections within the attention and EF cerebral systems in adults with childhood ADHD.

The demonstration of FA abnormalities in the CB and SLF II in adults with childhood ADHD provides further support for persistent structural abnormalities into adulthood.”

Brain Imaging Data of ADHD. It’s Not Just 3 Neurotransmitters

Psychiatric Times August 2004 Vol. XXI Issue 9. Amir Raz, Ph.D.

“Neuroimaging assays have most consistently implicated abnormalities of the dorsal prefrontal cortex and basal ganglia in ADHD.

Reduced metabolic rates have been reported in the left sensorimotor area in children with ADHD and in the premotor and superior prefrontal cortices of adults with ADHD.

Positron emission tomography data from 10 adolescents with ADHD found reduced metabolic rates versus healthy controls in, among other regions, the left anterior frontal area, showing negative correlation with numerous symptom severity measure.

Smaller volumes of the right prefrontal cortex have been reported in children with ADHD compared with healthy controls.

Magnetic resonance imaging data demonstrated smaller right globus pallidus nuclei in boys with ADHD relative to a control group.

Individuals with ADHD had significantly smaller brain volumes in all regions, even after adjustment for significant covariates. This global difference was reflected in smaller total cerebral volumes and in significantly smaller cerebellar volumes.

Unmedicated children with ADHD also exhibited smaller total white matter volumes compared with controls and with medicated children with ADHD.

fMRI studies have reported abnormal activation of the striatum, prefrontal cortex and anterior cingulate cortex in ADHD.

Whereas control participants activated the anterior cingulate cortex, participants with ADHD seemed to rely on the anterior insula–a brain region typically associated with responses in more routine tasks not involving conflict.”

Brain Scans Reveal Physiology of ADHD

Psychiatric News. “New high-resolution, three-dimensional maps of the brains of children with attention-deficit hyperactivity disorder indicate significant and specific anatomical differences within areas of the brain thought to control attentional and inhibitory control systems, compared with brain scans of children without ADHD.

The images are thought to be the most advanced to date to reveal the anatomical basis of the disorder. Includes two 3d scan photos.”

Caudate Nucleus Volume Asymmetry Predicts ADHD Symptomatology In Children.

Journal of Child Neurology. 2002 Dec;17(12):877-84 Schrimsher GW, Billingsley RL, Jackson EF, Moore BD 3rd. Department of Psychology, University of Houston, Houston, TX, USA.

“A greater degree of right to left caudate volume asymmetry predicted subclinical inattentive behaviors in a sample of nonreferred children. This finding is congruent with neuroanatomic models of attention emphasizing lateralized alteration in prefrontal/striatal systems. The results support the view that clinical ADHD is the extreme of a behavioral continuum that extends into the normal population.”

Cerebral Glucose Metabolism In Adults With ADHD

The New England Journal of Medicine. “Researchers measured adults with ADHD with a PET scan.

None of the adults had ever been treated with stimulant medication.

RESULTS. Global cerebral glucose metabolism was 8.1 percent lower in the adults with hyperactivity than in the normal controls.

The largest reductions were in the premotor cortex and the superior prefrontal cortex–areas earlier shown to be involved in the control of attention and motor activity.

The largest reductions were in the premotor cortex and the superior prefrontal cortex–areas earlier shown to be involved in the control of attention and motor activity.”

Clinical Implications of the Perception of Time in Attention Deficit Hyperactivity Disorder (ADHD): A Review

Medical Science Monitor. By Radek Ptacek, Simon Weissenberger, Ellen Braaten, Martina Klicperova-Baker, Michal Goetz, Jiri Raboch, Martina Vnukova,and George B. Stefano.

“This review summarizes recent research on the perception of time in ADHD and proposes that this symptom is a possible diagnostic characteristic.

Controlled studies on time perception have compared individuals with ADHD with typically developing controls (TDCs) and have used methods that include the Zimbardo Time Perspective Inventory (ZTPI).

Practical approaches to time perception and its evaluation have shown that individuals with ADHD have difficulties in time estimation and discrimination activities as well as having the feeling that time is passing by without them being able to complete tasks accurately and well.

Although ADHD has been associated with neurologic abnormalities in the mesolimbic and dopaminergic systems, recent studies have found that when individuals with ADHD are treated medically, their perception of time tends to normalize.

The relationship between ADHD and the perception of time requires greater attention.”

Cortical Thinning of the Attention and Executive Function Networks in Adults with ADHD

Cerebral Cortex 2007 17(6):1364-1375. “ADHD has been associated with structural alterations in brain networks influencing cognitive and motor behaviors. Volumetric studies in children identify abnormalities in cortical, striatal, callosal, and cerebellar regions.

We carried out a structural magnetic resonance imaging study of cortical thickness in the same sample of adults with ADHD.

Compared with healthy adults, adults with ADHD showed selective thinning of cerebral cortex in the networks that subserve attention and EF.

In the present study, we found significant cortical thinning in ADHD in a distinct cortical network supporting attention especially in the right hemisphere involving the inferior parietal lobule, the dorsolateral prefrontal, and the anterior cingulate cortices.

This is the first documentation that ADHD in adults is associated with thinner cortex in the cortical networks that modulate attention and EF.”

Exploring Deficient Emotion Regulation In Adult ADHD: Electrophysiological Evidence

European Archives of Psychiatry and Clinical Neuroscience. “In this study, we provide meaningful electrophysiological evidence of ED in adult patients with ADHD (n = 39) compared to healthy controls (n = 40) by exploring the electrophysiological correlates of the emotion regulation strategies reappraisal, distraction, and expressive suppression.

Event-related potentials (ERPs) were recorded during passive viewing of neutral and negative images, as well as during emotion regulation.

The patients with ADHD exhibited increased frontal late positive potential (LPP) amplitudes during passive viewing of the aversive images and during emotion regulation.

Compared with the healthy controls, a subgroup of medication-naïve patients with ADHD (n = 25) also exhibited larger centroparietal LPP amplitudes and provided more negative ratings of the aversive and neutral images.

Both the frontal and centroparietal LPP amplitudes were associated with ADHD symptom severity.

However, no significant deficit in LPP modulation during emotion regulation was found.

These findings strongly support the clinical observation of increased emotional responsivity toward negative stimuli and difficulty during the implementation of emotion regulation strategies and thus encourage the implementation of emotion regulation modules in the treatment of adult patients with ADHD.”

Fluid Reasoning Deficits in Children with ADHD: Evidence from fMRI

Brain Research. “Twenty-two right-handed, non-medicated children (12 ADHD, 10 controls) ages 8–12 years completed a fluid reasoning task during which fMRI data were collected.

Fluid reasoning, also known as analogical or relational reasoning, is the ability to manipulate representations among stimuli in order to reason, plan, and problem solve using attentional, working memory, and cognitive perceptual skills.

It involves relational integration, inhibitory control, and resolution of interference and is considered a core component of fluid intelligence.

In fact, fluid reasoning appears critical for all tasks identified with executive functioning and may comprise an executive function resource that influences self-regulation of cognition and behavior.

The primary comparison of interest was activation during the fluid reasoning compared to the control condition.

Behavioral data showed that children with ADHD tended to be less accurate with faster reaction times in the fluid reasoning condition compared to controls, and were significantly less accurate in the control condition.

Controls activated more than participants with ADHD in the right intraparietal sulcus and the left lateral cerebellum in the fluid reasoning condition.

Results showed hypoactivation in ADHD in regions critical for fluid reasoning. These results add to the literature suggesting a role for parietal and cerebellar regions in cognition and ADHD.

Deficits in fluid reasoning may be related to cognition and behavior deficits in ADHD.

Results showed hypoactivation in ADHD in regions critical for fluid reasoning,

Findings suggest particular deficits in parietal/cerebellar regions.”

High-Resolution Brain SPECT Imaging in ADHD

Annals of Clinical Psychiatry. Daniel G. Amen, M.D and Blake D. Carmichael, BA

“Brain SPECT (single-photon emission computed tomography) imaging is a nuclear medicine study which may offer the most widely available and widely applicable measure of neuronal behavior (1). SPECT measures cerebral blood flow and, indirectly, brain metabolism

Children and adolescents with ADHD were evaluated with high-resolution brain SPECT imaging to determine if there were similarities between reported PET and QEEG findings.

Fifty-four children and adolescents with ADHD by DSM-III-R and Conners Rating Scale criteria were evaluated. A non-ADHD control group was also studied with SPECT.

Two brain SPECT studies were done on each group, a resting study and an intellectual stress study done while participants were doing a concentration task.

Sixty-five percent of the ADHD group revealed decreased perfusion in the prefrontal cortex with intellectual stress, compared to only 5% of the control group.

These are findings consistent with PET and QEEG findings.

Of the ADHD group who did not show decreased perfusion, two-thirds had markedly decreased activity in the prefrontal cortices at rest.”

Improvements in Executive Function Correlate with Enhanced Performance and Functioning and Health-Related Quality of Life: Evidence from 2 Large, Double-Blind, Randomized, Placebo-Controlled Trials in ADHD

Postgraduate Medicine. Dr. Thomas E. Brown.

“Objective: To assess whether improvement in executive function correlates with perceived improvement in health-related quality of life (HRQOL) in adults with attention-deficit/hyperactivity disorder (ADHD) who are treated with stimulant medication

Methods: We collected data on executive function and HRQOL using the Brown Attention-Deficit Disorder Scale (BADDS) and the ADHD Impact Module–Adult (AIM-A) during 2 large, randomized, double-blind, placebo-controlled trials evaluating the use of the triple-bead mixed amphetamine salt (MAS) SPD465 as stimulant pharmacotherapy for ADHD. BADDS and AIM-A data were collected at baseline and at study endpoint, and changes from baseline were assessed.

Correlation coefficients for BADDS and AIM-A were calculated at baseline and endpoint for each study. Results: The change from baseline in BADDS total score was –14.8 ± 24.49 in Study 1 (dose optimization strategy) and –26.1 ± 28.54 in Study 2 (forced-dose titration strategy), demonstrating substantial reported improvement in executive function.

In both studies, improvement was reported for all 5 BADDS clusters at study endpoint versus baseline.

While improvement was reported for all 6 AIM-A scales at study endpoint versus baseline, the most substantial change from baseline in AIM-A scores over the course of the studies was in Performance and Function (Study 1, +15.2 ± 25.68; Study 2, +26.3 ± 28.17).

There was significant correlation of the BADDS total score with the AIM-A Performance and Function scale (Study 1, –0.6723; Study 2, –0.6982), and strong correlations were observed between each of the 5 individual clusters of BADDS and AIM-A performance and function in both studies.

Conclusions: Reported improvement in executive function correlates with reported improvement in HRQOL as assessed in 2 independent clinical trials in which participants received either placebo or triple-bead MAS for the treatment of ADHD.

In particular, there were strong correlations between all 5 individual clusters of BADDS and the AIM-A Performance and Function scale.”

Inhibitory Control of Memory Retrieval and Motor Processing Associated with the Right Lateral Prefrontal Cortex: Evidence from Deficits in Individuals with ADHD

Neuropsychologia. “The current study examined whether inhibitory difficulties in ADHD extend to inhibitory control over memory retrieval.

During fMRI 16 individuals with ADHD and 16 controls performed the Think/No-Think (TNT) task. Behaviorally, the Stop Signal Reaction Time task (SSRT) was used to assess inhibitory control over motor responses.

To link both of these measures to behavior, the severity of inattentive and hyperactive symptomatology was also assessed.

Behaviorally, ADHD individuals had specific difficulty in inhibiting, but not in elaborating/increasing memory retrieval, which was correlated with symptom severity and longer SSRT.

Additionally, ADHD individuals showed reduced activity in rLPFC during the TNT, as compared to control individuals.

Moreover, unlike controls, in whom the correlation between activity of the rMFG and hippocampus predicts inhibitory success, no such correlation was observed for ADHD individuals.

Moreover, decreased activity in rIFG in individuals with ADHD predicted a decrease in the ability to inhibit motor responses.

These results suggest that inhibitory functions of rLPFC include control over both memory and motoric processes. They also suggest that inhibitory deficits in individuals with ADHD extend to the memory domain.”

International Consensus Statement on ADHD PDF

From Attitude Magazine. 75 international scientists were deeply concerned about the periodic inaccurate portrayal of ADHD in media reports. So they “created this consensus statement on ADHD as a reference on the status of the scientific findings concerning this disorder, its validity, and its adverse impact on the lives of those diagnosed with the disorder as of this writing (January 2002)”

Here’s one particular quote I like

“To publish stories that ADHD is a fictitious disorder or merely a conflict between today’s Huckleberry Finns and their caregivers is tantamount to declaring the earth flat, the laws of gravity debatable, and the periodic table in chemistry a fraud.”

Intrinsic Affective Network Is Impaired in Children with Attention-Deficit/Hyperactivity Disorder

PLOS.One. By New-Fei Ho, Joanna S. X. Chong, Hui Li Koh, Eleni Koukouna, Tih-Shih Lee, Daniel Fung, Choon Guan Lim, Juan Zhou.

“In this study, we use resting-state functional magnetic resonance imaging to test the hypothesis of diminished functional integration within the affective/limbic network (which includes the amygdala, hippocampus, subgenual cingulate cortex, orbitofrontal cortex and nucleus accumbens) of children with ADHD, which is associated with their behavioral measures of emotional control deficits.

Resting state-fMRI data were obtained from 12 healthy control subjects and 15 children with ADHD, all who had a minimum one-month washout period for medications and supplements.

Children with ADHD demonstrated less integrated affective network, evidenced by increased bilateral amygdalar and decreased left orbitofrontal connectivity within the affective network compared to healthy controls.

The hyper-connectivity at the left amygdalar within the affective network was associated with increased aggressiveness and conduct problems, as well as decline in functioning in children with ADHD. Similar findings in affective network dysconnectivity were replicated in a subset of children with ADHD three months later.

Our findings of divergent changes in amygdala and orbitofrontal intrinsic connectivity support the hypothesis of an impaired functional integration within the affective network in childhood ADHD.

Larger prospective studies of the intrinsic affective network in ADHD are required, which may provide further insight on the biological mechanisms of emotional control deficits observed in ADHD.”

Pharmaco-Meg Evidence For Attention Related Hyper-Connectivity Between Auditory And Prefrontal Cortices In ADHD

Psychiatry Research: Neuroimaging. “Both hyper- and hypo-activation in the dorsolateral prefrontal cortex, DLPFC, has been reported in patients with attention-deficit hyperactivity disorder (ADHD) during many different cognitive tasks, but the network-level effects of such aberrant activity remain largely unknown.

Using magnetoencephalography (MEG), we examined functional connectivity between regions of the DLPFC and the modality-specific auditory cortices during an auditory attention task in medicated and un-medicated adults with ADHD, and those without ADHD.

Participants completed an attention task in two separate sessions (medicated/un-medicated), and each session consisted of two blocks (attend and no-attend). All MEG data were coregistered to structural MRI, corrected for head motion, and projected into source space.

Subsequently, we computed the phase coherence (i.e., functional connectivity) between DLPFC regions and the auditory cortices.

We found that un-medicated adults with ADHD exhibited greater phase coherence in the beta (14–30Hz) and gamma frequency (30–56 Hz) range in attend and no-attend conditions compared to controls.

Stimulant medication attenuated these differences, but did not fully eliminate them. These results suggest that aberrant bottom-up processing may engulf executive resources in ADHD.”

Neural Network Topology In ADHD; Evidence For Maturational Delay And Default-Mode Network Alterations

“Clinical Neurophysiology.

OBJECTIVE:

Attention-deficit/hyperactivity disorder (ADHD) has been associated with widespread brain abnormalities in white and grey matter, affecting not only local, but global functional networks as well. In this study, we explored these functional networks using source-reconstructed electroencephalography in ADHD and typically developing (TD) children. We expected evidence for maturational delay, with underlying abnormalities in the default mode network.

METHODS:

Electroencephalograms were recorded in ADHD (n=42) and TD (n=43) during rest, and functional connectivity (phase lag index) and graph (minimum spanning tree) parameters were derived. Dependent variables were global and local network metrics in theta, alpha and beta bands.

RESULTS:

We found evidence for a more centralized functional network in ADHD compared to TD children, with decreased diameter in the alpha band (ηp2=0.06) and increased leaf fraction (ηp2=0.11 and 0.08) in the alpha and beta bands, with underlying abnormalities in hub regions of the brain, including default mode network.

CONCLUSIONS:

The finding of a more centralized network is in line with maturational delay models of ADHD and should be replicated in longitudinal designs.

SIGNIFICANCE:

This study contributes to the literature by combining high temporal and spatial resolution to construct EEG network topology, and associates maturational-delay and default-mode interference hypotheses of ADHD.”

PET, SPECT Studies Find More Evidence of Dopamine’s Role in ADHD

From Medscape. Free registration required. “Studies using positron emission tomography (PET) and other approaches suggest new details about the underlying biology of ADHD. Released here at the 50th annual meeting of the Society of Nuclear Medicine.” 3 different studies mentioned.

Real Science Defines ADHD As A Real Disorder

From CHADD. “Some of the most prestigious scientific-based organizations in the world conclude that ADHD is a real disorder with potentially devastating consequences when not properly identified, diagnosed, and treated. Excerpts from the following organizations.

American Medical Association (AMA), Surgeon General of the United States, National Institutes of Health (NIH), Centers for Disease Control and Prevention (CDC), American Academy of Pediatrics (AAP), American Academy of Child and Adolescent Psychiatry (AACAP)”

Regional Gray Matter Volume Differences Between Adolescents With ADHD and Typically Developing Controls: Further Evidence for Anterior Cingulate Involvement.

Journal of Attention Disorders.

“METHOD:

Voxel-based morphometry (VBM) using the DARTEL approach was performed to assess regional gray matter (GM) volumes. Additionally, individual performance on tests of attention was recorded to correlate ADHD related cognitive impairments with regional gray matter abnormalities.

RESULTS:

We found significantly smaller GM volume in subjects with ADHD compared to their matched controls within the anterior cingulate cortex (ACC), the occipital cortex, bilateral hippocampus/amygdala and in widespread cerebellar regions. Further, reductions of the ACC gray matter volume were found to correlate with scores of selective inattention.

CONCLUSION:

These findings underline that structural alterations in a widespread cortico-subcortical network seem to underlie the observable attention problems in patients with ADHD.”

Some Myths of ADHD

From CHADD USA with links to clinical evidence.

“Myth # 1: ADHD is Not a Real Disorder
Myth # 2: ADHD is a Disorder of Childhood
Myth # 3: ADHD is Over-Diagnosed
Myth # 4: Children with ADHD are Over-medicated
Myth # 5: Poor Parenting Causes ADHD
Myth # 6: Minority Children are Over-Diagnosed with ADHD and are Over-Medicated
Myth # 7: Girls Have Lower Rates and Less Severe ADHD than Boys”

Timing Deficits In Attention-Deficit/Hyperactivity Disorder (ADHD): Evidence From Neurocognitive And Neuroimaging Studies

Neuropsychologia. “The present review provides a synthetic overview of the evidence for neurocognitive and neurofunctional deficits in ADHD in timing functions, and integrates this evidence with the cognitive neuroscience literature of the neural substrates of timing.

The review demonstrates that ADHD patients are consistently impaired in three major timing domains, in motor timing, perceptual timing and temporal foresight, comprising several timeframes spanning milliseconds, seconds, minutes and longer intervals up to years.

The most consistent impairments in ADHD are found in sensorimotor synchronisation, duration discrimination, reproduction and delay discounting.

These neurocognitive findings of timing deficits in ADHD are furthermore supported by functional neuroimaging studies that show dysfunctions in the key inferior fronto-striato-cerebellar and fronto-parietal networks that mediate the timing functions.

Although there is evidence that these timing functions are inter-correlated with other executive functions that are well established to be impaired in the disorder, in particular working memory, attention, and to a lesser degree inhibitory control, the key timing deficits appear to survive when these functions are controlled for, suggesting independent cognitive deficits in the temporal domain.

There is furthermore strong evidence for an association between timing deficits and behavioural measures of impulsiveness and inattention, suggesting that timing problems are key to the clinical behavioural profile of ADHD.

Emerging evidence shows that the most common treatment of ADHD with the dopamine agonist and psychostimulant Methylphenidate attenuates most timing deficits in ADHD and normalises the abnormally blunted recruitment of the underlying fronto-striato-cerebellar networks.

Timing function deficits in ADHD, therefore, next to executive function deficits, form an independent impairment domain, and should receive more attention in neuropsychological, neuroimaging, and pharmacological basic research as well as in translational research aimed to develop pharmacological or non-pharmacological treatment of abnormal timing behaviour and cognition in ADHD.”

Two Anterior Regions Of The Corpus Callosum Were Significantly Smaller In ADHD Boys.

By Dr P.V.F. Cosgrove Consultant Child and Adolescent psychiatrist. “MRI scans assessed the frontal circuitry in 18 ADHD boys in comparison to 18 matched controls.

They found that two anterior regions of the corpus callosum (the rostrum and the rostral body) were significantly smaller and concluded that this was evidence for frontal lobe dysfunction and abnormal development.

The callosal fibres in the rostral body relate to the premotor cortex, which is critical for “the suppression of relatively automatic responses to certain sensory stimuli”.

This is consistent with a defect in the person’s ability to inhibit responses, which is considered by Barkley to be the fundamental deficit in ADHD.”

Volumetric MRI Analysis Comparing Subjects Having ADHD With Normal Controls.

Neurology. “Case-control study. Despite similar hemispheric volumes, ADHD subjects had smaller volumes of (1) left total caudate and caudate head (p <0.04), with reversed asymmetry (p < 0.03); (2) right anterior-superior (frontal) region en bloc (p < 0.03) arid white matter (p < 0.01); (3) bilateral anterior-inferior region en bloc (p <0.04); and (4) bilateral retrocallosal (parietal-occipital) region white matter (p < 0.03).

Possible structural correlates of ADHD response to stimulants were noted in an exploratory analysis, with the smallest and symmetric caudate, and smallest left anterior-superior cortex volumes found in the responders, but reversed caudate asymmetry and the smallest retrocallosal white matter volumes noted in the nonresponders.”

How To Manage Adult ADHD