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Understanding Attention Deficit: The New ADHD

What's new about ADHD? A lot, according to Yale professor Thomas Brown, Ph.D. You'll think differently about the condition once you get all the facts.

By Thomas Brown, Ph.D.

ADHD 2.0

Findings from neuroscience, brain imaging, and clinical research have dramatically changed the old understanding of ADHD as essentially a behavior disorder. Experts now see ADHD as a developmental impairment of the brain's self-management system, its executive functions. There are many other myths about ADHD, as you will see. So update your thinking about the condition with the facts.  

New vs. Old Models

The new model of ADHD differs in many ways from the earlier model of this disorder as a cluster of behavior problems in young children. The new model is a paradigm shift for understanding ADHD. It applies to children and adolescents and adults. It focuses on a wide range of self-management functions linked to complex brain operations, and these are not limited to readily observable behaviors. But there is substantial  overlap between the old and new ADHD models.

On-and-Off Focus

Clinical data indicate that executive function impairments are situationally-variable; each person with ADHD tends to have some specific activities or situations in which she has no difficulty in using executive functions that are significantly impaired for her in most other situations. Typically, these are activities in which the ADDer has a strong personal interest or about which he believes something unpleasant will follow quickly if he does not do the task right now. 

Signs in Childhood

Recent research has shown that many with ADHD function well during childhood and do not manifest any significant symptoms until adolescence or later, when greater challenges to executive function are encountered. Over the past decade research has shown that impairing symptoms of ADHD often persist well into adulthood. However, studies have also shown that some individuals with ADHD during childhood experience significant reductions in their impairments as they grow older.

High IQ and ADHD

Intelligence as measured by IQ tests has virtually no systematic relationship to the executive function impairments described in the new model of ADHD. Studies have shown that even extremely high-IQ children and adults can suffer impairments of ADHD. This causes them problems in deploying their strong cognitive skills consistently and effectively in many life situations. 

Emotional Connection

Recent research has shown the important role of emotions in ADHD. Some research has focused solely on the problems in regulating emotions without sufficient inhibition. Research has also shown that a chronic deficit in emotions that comprise motivation is an impairment for most individuals. This makes it hard for them to arouse and sustain motivation for activities that don't give immediate and continuing reinforcement.

Mapping Deficits

Executive functions are complex and involve not only the prefrontal cortex, but many other components of the brain. Individuals with ADHD have been shown to differ in the rate of maturation of specific areas of the cortex, in the thickness of the cortical tissue, in characteristics of the parietal and cerebellar regions, as well as in the basal ganglia, and in the white matter tracts that connect and provide critically important communication between various regions of the brain.

Chemical Imbalance

Impairments of ADHD are not due to a global excess or lack of a specific chemical within or around the brain. The primary problem is related to chemicals manufactured, released, and reloaded at the level of synapses, the junctions between certain networks of neurons that manage the brain's management system. Persons with ADHD tend not to release enough of these essential chemicals, or to release and reload them too quickly. ADHD medication helps to improve this process.

The ADHD Gene

No single gene or genes have been identified as a cause of the impairments known as ADHD. Recent research has identified two different groupings that together are associated with, though not definitively causal of, ADHD. At this point, the complexity of the disorder is likely to be associated with multiple genes, each of which, in itself, has only a small effect upon development of ADHD.


The incidence of oppositional defiant disorder (ODD) in children with ADHD ranges from 40 to 70%. The higher rates are usually for persons with the combined type of ADHD. ODD is characterized by chronic problems with negativistic, disobedient, defiant and/or hostile behavior toward authority figures. Typically, ODD is apparent at about 12 years of age and persists for about six years and then gradually remits. More than 70% of kids diagnosed with ODD never develop Conduct Disorder.

ADHD and Autism

Research has demonstrated that many individuals with ADHD have significant traits related to Autistic Spectrum Disorders, and that many persons diagnosed with disorders on the Autistic Spectrum also meet criteria for ADHD. Studies have also shown that ADHD medications can be helpful in alleviating ADHD impairments in individuals on the Autistic Spectrum. ADHD medications can also help those on the Autistic Spectrum with ADHD to improve on some of their impairments. 

Meds and Brain Changes

Studies and clinical trials have shown that ADHD medications give the following benefits to some children and adults: 
> improve working memory, classroom behavior, the motivation to execute tasks, and to persist in solving problems
> minimize boredom, distractibility when doing tasks, and emotional outbursts
> increase test performance, rates of graduation, and other achievements that can have lasting effects
> normalize structural abnormalities in specific brain regions

Meds for Different Ages

Fine-tuning the dose and timing of stimulants is important because the most effective dose depends on how sensitive the patient's body is to that specific medication. Usually doctors start with a very low dose and gradually increase it until an effective dose is found, significant adverse effects occur, or the maximum recommended dose is reached. Some adolescents and adults need smaller doses than those taken by children; some young children need larger doses than most of their peers.

Preschoolers and Meds

Research has shown that a majority of children aged 3 to 5 1/2 years with moderate to severe ADHD had significant improvement in symptoms when treated with stimulants. Side effects are slightly more common than is usually seen in older children, but still minimal. In 2012, the AAP recommended that children aged four to five with significant ADHD impairments should be treated with behavior therapy. If not effective after nine months, stimulant medication is recommended.

Impulsive Forever?

Many with ADHD never manifest excessive levels of hyperactivity or impulsivity in childhood or beyond. Among those who are more "hyper" and impulsive in childhood, a substantial percentage outgrow the symptoms by middle childhood or early adolescence. But impairments in focusing and sustaining attention, organizing tasks, managing emotions, and using working memory may persist and become problematic, as the person enters adolescence and adulthood.

ADHD Is Different

ADHD differs from many other disorders in that it cross-cuts other disorders. The executive function impairments that constitute ADHD underlie other disorders as well. Many learning and psychiatric disorders could be compared to problems with a specific computer software package that, when not working well, interferes with a few functions. ADHD might be compared to a problem in the computer's operating system that is likely to interfere with the operation of many different programs.

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