Part 2: Executive Function in Adolescence
MYTH: EFS and Adolescence
Executive function impairments of ADHD usually are outgrown when the person reaches her late teens or early twenties.
THE FACTS: Some children with ADHD gradually outgrow their ADHD-related impairments as they get into middle childhood or adolescence. For them, ADHD is a variety of developmental lags. Most often hyperactive and/or impulsive symptoms improve as the individual reaches adolescence, while the broad range of inattention symptoms persist and sometimes get worse. Often the most problematic period is during junior high, high school, and the first few years of college. That is the time when the individual faces the widest range of challenging activities without opportunity to escape from the ones in which they have little interest or ability. After that period, some with ADHD are fortunate enough to find a job and a life situation in which they can build on their strengths and work around their cognitive weaknesses.
MYTH: Mapping Deficits
Modern research methods have established that executive function impairments are localized mainly in the prefrontal cortex.
THE FACTS: Executive functions are complex and involve not only the prefrontal cortex, but also 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.
Recent research has also shown that those with ADHD tend to have different patterns in functional connectivity, patterns of oscillations that allow different regions of the brain to exchange information.
MYTH: A Brain Chemical Problem?
ADHD-related executive function impairments are due primarily to a "chemical imbalance" in the brain.
THE FACTS: The term "chemical imbalance in the brain" is often used to explain impairments of ADHD. This suggests that there are chemicals floating around in the cerebral spinal fluid that surrounds the brain that are not in correct proportions, as though there were too much salt in the soup. This assumption is wrong. 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 then reloaded at the level of synapses, the trillions of infinitesimal junctions between certain networks of neurons that manage critical activities within the brain's management system.
The brain is essentially a huge electrical system that has multiple subsystems that need to communicate with one another constantly to get anything done. This system operates on low-voltage electrical impulses that carry messages from one tiny neuron to another in fractions of a second. However, these neurons are not physically connected; there are gaps at each point of connection. To get from one neuron to another, an electrical message needs to jump the gap. Arrival of the electrical impulse causes tiny "micro-dots" of a neurotransmitter chemical to be released. This works like a spark plug to carry the message across the gap and further down the circuit.
Persons with ADHD tend not to release enough of these essential chemicals, or to release and reload them too quickly, before an adequate connection has been made. Medications used to treat ADHD help to improve this process.
MYTH: The ADHD Gene
Recent research has identified a gene that causes executive function problems in persons with ADHD.
THE FACTS: Despite extensive exploration of the genome and the high heritability rate of ADHD, no single gene or genes have been identified as a cause of the syndrome of impairments known as ADHD. Recent research has identified two different groupings that together are associated with, though not definitively causal of, ADHD. This combination of some common variant genes and a group of deletions or duplications of multiple rare variants offers some promise of further progress in the search for genetic factors contributing to ADHD. However, 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.
MYTH: ODD and ADHD
Most children with ADHD also have behavior problems of Oppositional Defiant Disorder, which usually lead to the more severe behaviors of Conduct Disorder.
THE FACTS: Among children with ADHD, reported incidence of Oppositional Defiant Disorder (ODD) ranges from 40 percent to 70 percent. The higher rates are usually for persons with the combined type of ADHD rather than the inattentive type. This disorder is characterized by chronic problems with negativistic, disobedient, defiant and/or hostile behavior toward authority figures. It tends to involve difficulties with management of frustration, anger, and impulsive negative reactions when frustrated. Typically, ODD is apparent at about 12 years of age and persists for approximately six years and then gradually remits. More than 70 percent of children diagnosed with this disorder never go on to meet diagnostic criteria for Conduct Disorder, a diagnosis that reflects much more severe behavior problems.
Next: ADHD and Autism
This article appears in the Fall issue of ADDitude.
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