Driven Distraction

It is a neurobehavioral developmental disorder affecting about 3-5% of the world’s population. It typically presents itself during childhood, and is characterized by a persistent pattern of inattention and/or hyperactivity, as well as forgetfulness, poor impulse control or impulsivity, and distractibility. ADHD is currently considered to be a persistent and chronic condition for which no medical cure is available, although medication can be prescribed. ADHD is most commonly diagnosed in children and, over the past decade, has been increasingly diagnosed in adults. About 60% of children diagnosed with ADHD retain the condition as adults. It appears to be highly heritable, although one-fifth of all cases are estimated to be caused from trauma or toxic exposure. Methods of treatment usually involve some combination of medications, behavior modifications, life style changes, and counseling.

The scientific consensus in the field, and the consensus of the national health institutes of the world, is that ADHD is a disorder which impairs functioning, and that many adverse life outcomes are associated with ADHD.

The most common symptoms of ADHD are distractibility, difficulty with concentration and focus, short term memory loss, procrastination, problems organizing ideas and belongings, tardiness, impulsivity, and weak planning and execution. Not all people with ADHD exhibit all symptoms. The Diagnostic and Statistical Manual of Mental Disorders categorises the symptoms of ADHD into two clusters: Inattention symptoms and Hyperactivity/Impulsivity symptoms. Most ordinary people exhibit some of these behaviors but not to the point where they seriously interfere with the person’s work, relationships, or studies or cause anxiety or depression. Children do not often have to deal with deadlines, organization issues, and long term planning so these types of symptoms often become evident only during adolescence or adulthood when life demands become greater.

According to an advanced high-precision imaging study at the United States National Institutes of Health’s National Institute of Mental Health, a delay in physical development in some brain structures, with a median value of three years, was observed in the brains of 223 ADHD patients beginning in elementary school, during the period when cortical thickening during childhood begins to change to thinning following puberty. The delay was most prominent in the frontal cortex and temporal lobe, which are believed responsible for the ability to control and focus thinking, attention and planning, suppress inappropriate actions and thoughts, remember things from moment to moment, and work for reward, all functions whose disturbance is associated with a diagnosis of ADHD; the region with the greatest average delay, the middle of the prefrontal cortex, lagged a full five years in development in the ADHD patients. In contrast, the motor cortex in the ADHD patients was seen to mature faster than normal, suggesting that both slower development of behavioral control and advanced motor development might both be required for the restlessness and fidgetiness that characterize an ADHD diagnosis. Aside from the delay, both groups showed a similar back-to-front development of brain maturation with different areas peaking in thickness at different times. This contrasts with the pattern of development seen in other disorders such as autism, where the peak of cortical thickening occurs much earlier than normal.

The same laboratory had previously found involvement of the "7-repeat" variant of the dopamine D4 receptor gene, which accounts for about 30 percent of the genetic risk for ADHD, in unusual thinness of the cortex of the right side of the brain; however, in contrast to other variants of the gene found in ADHD patients, the region normalized in thickness during the teen years in these children, coinciding with clinical improvement. Hyperactivity is common among children with ADHD but tends to disappear during adulthood. However, over half of children with ADHD continue to have symptoms of inattention throughout their lives.

Inattention and "hyperactive" behavior are not the only problems with children with ADHD. ADHD exists alone in only about 1/3 of the children diagnosed with it. Many of these co-existing conditions require other courses of treatment and should be diagnosed separately instead of being grouped in the ADHD diagnosis. Some of the associated conditions are: a. Oppositional Defiant Disorder (35%) and Conduct Disorder (26%). These are both characterized by extreme anti-social behaviors. These disorders are frequently characterized by aggression, frequent temper tantrums, deceitfulness, lying, or stealing. b. Primary Disorder of Vigilance. Characterized by poor attention and concentration, as well as difficulties staying awake. These children tend to fidget, yawn and stretch, and appear to be hyperactive in order to remain alert and active. c. Bipolar disorder. As many as 25% of children with ADHD may have bipolar disorder. Children with this combination may demonstrate more aggression and behavioral problems than those with ADHD alone. d. Anxiety Disorders. Commonly accompany ADHD, particularly Obsessive-Compulsive Disorder. OCD is believed to share a genetic component with ADHD, and shares many of its characteristics. Although children with ADHD have an inability to maintain attention, conversely, they may also fixate.

There is evidence of hypothalamic-pituitary-adrenal axis (HPA axis) abnormalities in ADHD patients due to stress.



Most of the time ADHD is inherited, but it can also be caused by problems with the pregnancy, the delivery, early childhood severe illness, environmental toxins, etc.



Additionally, SPECT scans found people with ADHD to have reduced blood circulation, and a significantly higher concentration of dopamine transporters in the striatum which is in charge of planning ahead. Medications focused on treating A.D.H.D.(such as methylphenidate) work because they force blood to flow in certain areas of the brain, such as those that control and regulate concentration, which usually don’t receive a normal or sufficient amount of blood flow or circulation in the brains of individuals with A.D.H.D. A study by the U.S. Department of Energy¿s Brookhaven National Laboratory in collaboration with Mount Sinai School of Medicine in New York suggest that it is not the dopamine transporter levels that indicate ADHD, but the brain’s ability to produce dopamine itself. The study was done by injecting 20 ADHD subjects and 25 control subjects with a radiotracer that attaches itself to dopamine transporters. The study found that it was not the transporter levels that indicated ADHD, but the dopamine itself. ADHD subjects showed lower levels of dopamine across the board. They speculated that since ADHD subjects had lower levels of dopamine to begin with, the number of transporters in the brain was not the telling factor. In support of this notion, plasma homovanillic acid, an index of dopamine levels, was found to be inversely related not only to childhood ADHD symptoms in adult psychiatric patients, but to "childhood learning problems" in healthy subjects as well.

Although there is evidence for dopamine abnormalities in ADHD, it is not clear whether abnormalities of the dopamine system are the molecular abnormality of ADHD or a secondary consequence of a problem elsewhere. Researchers have described a form of ADHD in which the abnormality appears to be sensory overstimulation resulting from a disorder of ion channels in the peripheral nervous system.

An early PET scan study found that global cerebral glucose metabolism was 8.1% lower in medication-naive adults who had been diagnosed as ADHD while children. The image on the left illustrates glucose metabolism in the brain of a ’normal’ adult while doing an assigned auditory attention task; the image on the right illustrates the areas of activity in the brain of an adult who had been diagnosed with ADHD as a child when given that same task; these are not pictures of individual brains, which would contain substantial overlap, these are images constructed to illustrate group-level differences. Additionally, the regions with the greatest deficit of activity in the ADHD patients (relative to the controls) included the premotor cortex and the superior prefrontal cortex. A second study in adolescents failed to find statistically significant differences in global glucose metabolism between ADHD patients and controls, but did find statistically significant deficits in 6 specific regions of the brains of the ADHD patients (relative to the controls). Most notably, lower metabolic activity in one specific region of the left anterior frontal lobe was significantly inversely correlated with symptom severity. These findings strongly imply that lowered activity in specific regions of the brain, rather than a broad global deficit, is involved in ADHD symptoms. However, these readings are of subjects doing an assigned task. They could be found in ADHD diagnosed patients because they simply were not attending to the task. Hence the parts of the brain used by others doing the task would not show equal activity in the ADHD patients.



The estimated contribution of non-genetic factors to the contribution of all cases of ADHD is 20 percent.



The environmental factors implicated are common exposures and include alcohol, in utero tobacco smoke and lead exposure, believed to stress babies prenatally. Lead concentration below the Center for Disease Control’s action level account for slightly more cases of ADHD than tobacco smoke (290 000 versus 270 000, in the USA, ages 4 to 15). Complications during pregnancy and birth¿including premature birth¿might also play a role. It has been observed that women who smoke while pregnant are more likely to have children with ADHD. This could be related to the fact that nicotine is known to cause hypoxia (lack of oxygen) in utero, but it could also be that ADHD women have more probabilities to smoke both in general and during pregnancy, being more likely to have children with ADHD due to genetic factors.

Another factor that may be correlated with ADHD is mobile phone usage. A study surveying over 13,000 children found use of mobile phone handsets by pregnant mothers raised the risk of hyperactivity, emotional problems, and conduct problems, much to the researchers’ surprise.



Studies have found that malnutrition is also correlated with attention deficits. Diet seems to cause ADHD symptoms or make them worse. Many studies point to synthetic preservatives and artificial coloring agents aggravating ADD & ADHD symptoms in those affected. Older studies were inconclusive quite possibly due to inadequate clinical methods of measuring offending behavior. Parental reports were more accurate indicators of the presence of additives than clinical tests. Several major studies show academic performance increased and disciplinary problems decreased in large non-ADD student populations when artificial ingredients, including artificial colors were eliminated from school food programs.. Professor John Warner stated, ’significant changes in children¿s hyperactive behaviour could be produced by the removal of artificial colourings and sodium benzoate from their diet.’ and ’you could halve the number of kids suffering the worst behavioural problems by cutting out additives’.

In 1982, the NIH had determined, based on research available at that time, that roughly 5% of children with ADHD could be helped significantly by removing additives from their diet. The vast majority of these children were believed to have food allergies. More recent studies have shown that approximately 60-70% of children with and without allergies improve when additives are removed from their diet, that up to almost 90% of them react when an appropriate amount of additive is used as a challenge in double blind tests, and that food additives may elicit hyperactive behavior and/or irritability in normal children as well.



Head injuries can cause a person to present ADHD-like symptoms, possibly because of damage done to the patient’s frontal lobes. Because these types of symptoms can be attributable to brain damage, one earlier designation for ADHD was "Minimal Brain Damage".



There is no compelling evidence that social factors alone can create ADHD. Many researchers believe that attachments and relationships with caregivers and other features of a child’s environment have profound effects on attentional and self-regulatory capacities. It is noteworthy that a study of foster children found that an inordinate number of them had symptoms closely resembling ADHD. An editorial in a special edition of Clinical Psychology in 2004 stated that "our impression from spending time with young people, their families and indeed colleagues from other disciplines is that a medical diagnosis and medication is not enough. In our clinical experience, without exception, we are finding that the same conduct typically labelled ADHD is shown by children in the context of violence and abuse, impaired parental attachments and other experiences of emotional trauma." Furthermore, Complex Post Traumatic Stress Disorder can result in attention problems that can look like ADHD, as can Sensory Integration Disorders.