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Attention deficit hyperactivity disorder

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Attention-deficit hyperactivity disorder (ADHD) is one of the most commonly diagnosed mental disorders among children, although it also occurs in adults.

The brain on the left belongs to a person who does not have ADHD, the brain on the right belongs to a person who does have ADHD.

The official definition of ADHD is found in the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders-IV (Text Revision) (DSM-IV-TR), which also defines three subtypes of ADHD:

  • Predominantly Inattentive,
  • Predominantly Hyperactive-Impulsive, and
  • Combined Type.

Although most diagnoses of ADHD are made for children, the DSM definitions of ADHD do not confine the disorder solely to childhood and in fact many adults are also diagnosed. Current theory holds that approximately 30% of children diagnosed retain the disorder as adults. Although the disorder may not have been diagnosed in an individual during childhood, it is also currently thought that all adults with Adult attention-deficit disorder (AADD) had it in childhood. Hyperactivity and other symptoms may be less noticeable in adults with ADHD who have learned better coping skills and other forms of adaptive behavior than they had as children. Particularly in adults, studies have shown a high correlation between ADD and creativity. Many painters and performing artists seem to show significant evidence of ADD, particularly those drawn to improvisational humor and stand up comedy (see Robin Williams, the poster child for adult ADD).

Terminology

There is not yet a naming consensus. Below are listed several terms that have been used, past and present. One challenge in taxonomy is that some patterns of behavior are labeled by experts symptoms or sub-types of ADHD, while other experts label those same patterns as their own disorders, independent of ADHD. For the purposes of this article, the "Terminology" section will be used only to name ADHD and its near equivalents, while the names for its manifestations and subtypes will be listed in 'Symptoms', below.

  • Attention-deficit hyperactivity disorder (ADHD): In 1987, ADD was in effect renamed to ADHD in the DSM-III-R. In it, ADHD was broken down into three subtypes (see 'symptoms' for more details):
    • predominantly inattentive ADHD
    • predominantly hyperactive-impulsive ADHD
    • combined type ADHD
  • Attention deficit disorder (ADD): This term was first introduced in DSM-III, the 1980 edition. Is considered by some to be obsolete, and by others to be a synonym for the predominantly inattentive type of ADHD.
  • Attention-deficit syndrome (ADS): Equivalent to ADHD, but used to avoid the connotations of "disorder".
  • Hyperkinetic syndrome (HKS): Equivalent to ADHD, but largely obsolete in the United States, still used in some places world wide.
  • Minimal cerebral dysfunction (MCD): Equivalent to ADHD, but largely obsolete in the United States, though still commonly used internationally.
  • Minimal brain dysfunction or Minimal brain damage (MBD): Similar to ADHD, now obsolete.

Cause

Exact cause(s) of ADD are not conclusively known. Scientific evidence suggests most strongly that, in many cases, the disorder is genetically transmitted and is caused by an imbalance or deficiency in certain chemicals that regulate the efficiency with which the brain controls behavior.

A 1990 study at the National Institute of Mental Health correlated ADD with a series of metabolic abnormalities in the brain, providing further evidence that ADD is a neurological disorder. While heredity is often indicated, problems in prenatal development, birth complications, or later neurological damage can contribute to ADD.

The presumed causes under investigation include:

  • brain differences (brain scan technology has revealed differences in the size, symmetry, metabolism, and chemistry of the brain in those who have ADHD; however, it should be noted that there is yet no clear determination of the source of these differences).
  • genetics (children who have one parent with ADHD have a higher incidence of ADHD; current research is examining which genes are involved in ADHD). This investigative path also suggests environmental factors, handed down from generation to generation, that may trigger the symptoms associated with ADD.
  • brain development in utero and during the first year of life (possibly related to drug use during pregnancy or environmental toxins).

It has also been suggested that ADD may result from a poor diet and other factors rather than something inherent in sufferers. The study of changes in diets of children provide anecdotal and scientific evidence for this.

Research is ongoing in many studies.

Controversy

While ADD/ADHD is a known psychiatric condition, there are various theories about the cause and some controversy over the number of persons diagnosed and the cost of medications. Some denial in families may also relate to the negative perception of the condition as a hereditary brain disorder.

Hunter vs Farmer theory

A broad theory, not necessarily in conflict with the current medical research findings, is the hunter vs. farmer theory, which holds that in some ways, some ADD attributes in some humans may be a form of adaptive behavior developed over a long period to match the environment, or in easier terms, refinement of skills to suit needs. Under the theory, as civilized society evolved, the attributes of a hunter gave way to those of a farmer for most people as the survival skills needed changed. The hunter vs. farmer theory was first presented by Thom Hartmann, whose website describes him as "an internationally-known speaker on culture and communications, an author, and an innovator in the fields of psychiatry, ecology, and economics." [1]

ADD/ADHD a hoax?

There are some claims that ADD/ADHD is simply a hoax. Many of these charges are that there has been a conspiracy between medical and counseling professionals and the pharmaceutical companies, or that the former has been misled by the latter, which have profited greatly from the sale of medication such as Ritalin and Adderall, and have advertised their products extensively. Further, since medications became available there has been an increased number of persons diagnosed this might be explained by increased awareness or easy solution for doctors.

However, the results achieved in clinical tests with such medication and anecdotal evidence of parents, teachers, and both child and adult sufferers suggest there is both a condition and sucessful treatment options for most people who meet the criteria for a diagnosis.

A further problem is that ADD and ADHD are syndromes, associations of symptoms. There is no well established cause for the condition. This means that it may actually be a blanket term covering a multitude of conditions with a variety of causes.

Confusion may also arise from the fact ADD/ADHD symptom vary with each individual, and some mimic those of other causes. A known fact is that, as the body (and brain) matures and grows, the symptoms and adaptability of the individual also change. Many children diagnosed with ADD/ADHD seem to outgrow it as they mature. Clearly, other individuals experience the symptoms their entire lives.

Symptoms

  • In children the disorder is characterized by inattentiveness to external direction, impulsive behavior and restlessness. However, children with the inattentive type are actually often sluggish and hypo-active.
  • In adults the problem is often an inability to structure their lives and plan simple daily tasks. Thus, inattentiveness and restlessness often become secondary problems.

A diagnosis of ADHD is made based on a checklist of symptoms that can be found in DSM-IV-TR. A hyperlink to the Centers for Disease Control and Prevention (CDC) web page summarizing these criteria is given in the External links section below.

The CDC emphasizes that a diagnosis of ADHD should only be made by trained health care providers. This is important as many of the criteria can be readily misinterpreted and the prescribed drugs can be very dangerous.

Incidence

ADHD is considered by some to be a problem all over the industrialized world, although in no other country are children diagnosed with this disorder as often as in the United States.

According to the 2000 edition of DSM-IV-TR, ADHD affects three to seven percent of all children in the U.S. According to 2002 data from the CDC's annual National Health Interview Survey, released in 2004, nearly 4 million children younger than 18 in the United States had been diagnosed with attention deficit hyperactivity disorder (ADHD). The 2002 data indicated that twice as many boys were diagnosed with ADHD as girls (10% vs. 4%). Some experts theorize that ADHD is under-diagnosed in girls, since their symptoms tend to be less dramatic than those in boys and thus draw less attention from parents and teachers.

Psychological testing for ADHD

Psychological testing for ADHD symptoms generally consists of obtaining multiple types of assessments. These usually include a clinical interview reviewing the DSM-IV criteria for ADHD diagnosis. The interview also needs to rule out as much as possible other types of syndromes which can cause attention problems, such as depression, anxiety, allergies and psychosis. Rating scales can be administered which provide measurement of the person's own view of their symptoms, as well as the views of parents, teachers, and significant others. Finally, computerized tests of attention can be helpful in providing a further independent assessment. These different assessments may not be consistent, but do provide a view of the person's difficulties. Subjectivity of the analysis can be compounded by the fact that physicians generally need not order psychological testing in order to make the diagnosis of ADHD, but many doctors use this kind of assessment to avoid over-diagnosis and treatment. The process of obtaining referrals for such assessments is being promoted vigorously by the President's New Freedom Commission on Mental Health

Other forms of testing

Neurometrics, PET scans, or SPECT scans have been used for a more objective diagnosis. However, these are not usually suitable for very young children.


Treatment

There are many options available to treat people diagnosed with ADHD. These options include a variety of medications, behavior-changing therapies, and educational interventions.

Mainstream Treatment

The first-line medications used to treat ADHD mostly stimulants, including

  • Ritalin -- a trade name for methylphenidate. Generally lasts ~4 hours per dose. Often taken 3 times a day.
    • Ritalin SR -- SR stands for Sustained Release. Medication lasts 8 hours per dose and is usually taken twice a day.
    • Concerta -- An "all day" form of Ritalin which lasts 10-12 hours a day. Usually taken once or twice a day.
  • Adderall -- a trade name for a mixture of dextroamphetamine and laevoamphetamine salts. Duration: 4-6 hours a dose. A generic are available.
  • Adderall XR a longer lasting version of Adderall. Duration: 12 hours a day. Taken only once a day.
  • Desoxyn -- a trade name for methamphetamine, marketed by Ovation Pharma
  • Dexedrine-- trade name for dextroamphetamine.
  • Strattera (atomoxetine HCl), a selective norepinephrine reuptake inhibitor. Introduced in 2002. Duration: 24 hours. The first ever nonstimulant medication to be a first line treatment for ADHD.

Second-line medications include

  • benzphetamine -- a less powerful stimulant. Research on the effectiveness of this drug is not yet complete.
  • Provigil/modafinil -- Research on this drug is not yet complete.
  • Cylert/Pemoline --a stimulant used with great success until the late 1980s when it was discovered that this medication could cause liver damage. Although some physicians do continue to perscribe Cylert, it can no longer be considered a first-line medicine. In March 2005 the makers of Cylert announced that it would discontinue the medication's production.

Because most of the medications used to treat ADHD are Schedule II under the U.S. DEA schedule system, and are considered powerful stimulants with a potential for diversion and abuse, there is controversy surrounding prescribing these drugs for children and adolescents. However, research studying ADHD sufferers who either receive treatment with stimulants or go untreated has indicated that those treated with stimulants are in fact much less likely to abuse any substance than ADHD sufferers who are not treated with stimulants.{{1}}

Alternative treatments

There are many alternative treatments for ADHD, and all of them are as heavily disputed as the mainstream. This section attempts to deal with the most prominent of the alternative treatments.

Dr Ben F. Feingold, once a Professor of Allergy in San Francisco, claimed that hyperactivity was increasing in proportion to the level of food additives and proposed a specific diet believing that it would help 50% of hyperactive children.

The Feingold diet excluded cola drinks, chocolate, preservatives and flavour additives, as well as salicylates that occur naturally in fruit such as tomatoes, strawberries, pineapples and oranges. However pineapple juice was suggested as a "safe" drink.

The effectiveness of the Feingold diet has been heavily disputed. Most studies have shown that only 5% of children diagnosed with ADHD benefited from the diet (but this was obviously an important finding for that 5%). Other studies have shown a figure of 60%.


In the 1980s the vitamin B6 promoted as a helpful remedy for children with learning difficulties including inattentiveness. After that, zinc was promoted for ADD and autism. Multivitamins later became the claimed solution. Thus far, no reputable research has appeared to support any of these claims, except in cases of malnutrition.

There has been a lot of interesting work done with neurofeedback and ADHD. Children are taught, using video game-like technology, how to control their brain waves. This has a very high success rate, but is not widely used, or covered by insurance. Many professionals consider the treatment promising, but state that there is not yet sufficient evidence that it works after the immediate treatment is complete.

Possible Causes

ADHD is broadly defined and pervasive, and the symptoms attributed to ADHD likely have a variety of different causes. The initial triggers could include genetic vulnerabilities, viral or bacterial infections, brain injury, or nutritional deficits. There has been a surge in alternative approaches to ADHD, but these have been vigorously disputed.

Neuro-chemical imbalance

There is increasing evidence that variants in the gene for the dopamine transmitter are related to the development of ADHD (Roman et al., 2004, Am J Pharmacogenomics 4:83-92). This makes sense, as according to other recent studies, people with ADHD usually have an abnormally high number of dopamine neurotransmitters which discard the dopamine before the brain can fully make use of it. The stimulant medications used to treat the disorder are all capable of blocking dopamine neurotransmitters. Therefore, it is theorized that stimulant medication allows the brain to use its natural supply of dopamine more efficiently by blocking the dopamine transporters. Currently this theory is the most widely accepted in the scientific and medical community.

New studies consider the possibility that norepinephrine also plays a role. (see Krause, Dresel, Krause in Psycho 26/2000 p.199ff).

Smoking during pregnancy

The finding of another possible cause stemmed from the observation that children of women who smoked during pregnancy are more likely to be diagnosed with ADHD (Kotimaa et al., 2003, J Am Acad Child Adol Psychiatry 42, 826-833). Given that nicotine is known to cause hypoxia (too little oxygen) in the uterus, and that hypoxia causes brain damage, smoking during pregnancy could be an important contributing factor leading to ADHD. It may even help explain in part the increase in ADHD diagnoses, as the number of women smokers has increased. However, there are not nearly enough women smoking during pregnancy to account for all the ADHD diagnoses.

Deficiencies in Nutrition

It has been established conclusively that a small percentage of children are sensitive to dyes and other food additives, sugar, caffeine, etc. (Jacobson and Schardt, 1999, Diet, ADHD & Behavior, Center for Science in the Public Interest, Washington, DC).

Nutritional data has been well summarized in a review article (Burgess et al., 2000, Am J Clin Nutr 71:327-330). Children with ADHD have lower levels of key fatty acids. In fact, one study found that the lower the levels, the worse the symptoms. The possibility that fatty acid deficiency is a trigger for ADHD is especially plausible as nutrition scientists have recently demonstrated that the American diet is extremely deficient in omega-3 fatty acids. At the same time, ADHD diagnoses are rapidly increasing. More support for this idea comes from findings that breast-fed children have much lower levels of ADHD, and that until quite recently, infant formula contained NO omega-3 fatty acids. These findings are only correlational, and do not prove a conclusive connection.

Sleep Apnea

There is also new evidence that brief pauses in breathing (apnea) during infancy may be a cause of ADHD. Dr. Glenda Keating of Emory University presented data at the Society for Neuroscience annual meeting in October 2004, showing that repetitive drops in blood oxygen levels in newborn rats similar to that caused by apnea in some human infants is followed by a long-lasting reduction in dopamine levels, associated with ADHD. Apnea occurs in up to 85% of prematurely born human infants. (ScienceDaily)


Head Injuries

It has been known for some decades that head injuries can cause a person to experience and display ADHD-like symptoms.

Twentieth century history

  • 1902 -- the English pediatrician George Still described a condition analogous to ADHD. He regarded it as innate and not caused by the environment.
  • The 1918–1919 influenza pandemic left many survivors with encephalitis, affecting their neurological functions. Some of these exhibited immediate behavioural problems which correspond to ADD. This caused many to believe that the condition was the result of injury rather than genetics.
  • By 1966, following observations that the condition existed without any objectively observed pathological disorder or injury, researchers changed the terminology from Minimal Brain Damage to Minimal Brain Dysfunction. (Source: Oxford English Dictionary Online)
  • 1980 -- the name Attention Deficit Disorder (ADD) was first introduced in DSM-III, the 1980 edition.
  • 1994 -- DSM-IV described three groupings within ADHD, which can be simplified as: mainly inattentive; mainly hyperactive-impulsive; and both in combination.
  • 1998 -- the NIH developed and issued a Consensus Statement attesting to the existance of ADHD. A link is provided in the External Links section below.

Evidence for ADHD as an organic phenomenon

Brain imaging research using magnetic resonance imaging (MRI) has shown that differences exist between the brains of children with and without ADHD, though these differences have not been shown in any way to be pathological in nature. Additionally PET studies have shown there might be a link between a person's ability to pay continued attention to external directives and the use of glucose - the body's major fuel - in the brain. In adults diagnosed with ADHD, the brain areas that control attention use less glucose and appear to be less active, suggesting that a lower level of activity in some parts of the brain may cause inattention (Zametkin et al.). However, there is no evidence that this low level of glucose in fact causes the low level of attention to external direction; it could in fact be no more than an indicator for low attention, or in the alternative, superior self-direction.

Also worth noting are the results of some studies using SPECT (Single Photon Emission Computed Tomography). One study (Lou et al. in Arch. Neurol. 46(1989) 48-52) found people labeled as ADHD have reduced blood circulation in the striatum. But even more significant may be the discovery that people with ADHD seem to have a significantly higher concentration of dopamine transporters in the striatum (Dougherty et al. in Lancet 354 (1999) 2132-2133; Dresel et al. in Eur.J.Nucl.Med. 25 (1998) 31-39). Researchers have also shown that individuals labeled as either bipolar or ADHD often have varient dopamine receptor alleles. Researchers have reported, for example, that DRD4 7 repeat alleles appear more frequently in certain aboriginal cultures with low population densities such as the Amazon, whereas DRD4 2 repeat alleles are expecially common in higher population density regions, including the Orient.

Controversy and skepticism towards ADHD as a diagnosis

Critics have complained that the ADHD diagnostic criteria are sufficiently general or vague to allow virtually any child with persistent unwanted behaviors to be classified as having ADHD of one type or another.

Many people, including a growing number of critics, have wondered why the number of children diagnosed with ADHD in the U.S. and UK has grown so dramatically over a short period of time.

It has often been suggested that the causes of the apparent ADHD epidemic lie in cultural patterns that variously encourage or sanction the use of drugs as a simple and expeditious cure for complex problems that may stem primarily from social and environmental triggers rather than any innate disorder. Some critics assert that many children are diagnosed with ADHD and put on drugs as a substitute for parental attention, whereas many parents of ADHD children assert that the associated demand for attention goes beyond what can be humanly provided, causing massive disruption to other individuals and relationships, as well as to environments with dysfunctionally structured relationships such as are manifest in many classrooms. This criticism also includes the use of prescription drugs as a substitute for parental duties such as communication and supervision.

Thom Hartmann takes an approach from biological evolution to argue that ADHD is not a disorder, but an expression of biodiversity. In his book ADD - Attention Deficit Disorder (1997), Hartmann developed the idea that people having ADHD symptoms may have simply inherited a collection of genes that were selected for when hunting was particularly important. From an evolutionary point of view, it is quite acceptable that humans—like other animals—differ in their biology and pass on their traits from generation to generation. This idea is the basis of another of his works, The Edison Gene: ADHD and the Gift of the Hunter Child (2003).

Another source of skeptism towards making the diagnosis of "ADHD or not ADHD" may arise from the rising diagnosis of subclinical forms of ADHD. So called 'Shadow-syndromes' or 'sub-syndromes' stand for weaker forms of ADHD and are described in various degrees by John J. Ratey and Catherine Johnson on their book Shadow Syndromes: The Mild Forms of Major Mental Disorders That Sabotage Us.

Positive aspects

Though ADHD is classified as a serious disorder, many people have a different perspective and note the positive aspects. Some people believe that ADHD can be beneficial and find hints of ADHD in the lives of many famous people in history. Though such post mortem diagnosis is questionable, it is intriguing to ponder the evidence that people such as Thomas Edison might have been diagnosed as having ADHD if the current DSM criteria had been developed long ago. Other historical figures who have been proposed as ADHD candidates include: Hans Christian Andersen, Ludwig van Beethoven, Winston Spencer Churchill, Walt Disney, Benjamin Franklin, Robert and John F. Kennedy, Theodore Roosevelt, Jules Verne, Woodrow Wilson and the Wright brothers.

To see ADHD positively may seem somewhat problematic to anxious parents but it is at least a perspective that should be kept in mind. With or without hyperfocus, a common manifestation, ADD/ADHD in combination with successful coping skills may be utilized to achieve remarkable accomplishments. The list of historic figures and persons currently well-known in a wide range of fields who have displayed ADD/ADHD symptoms is impressive and may be source of inspiration.

See also List of famous people with attention-deficit hyperactivity disorder for those who either definitely have (or had) ADD/ADHD or it is thought be likely.

Adults

Although most diagnoses of ADHD are made for children, the DSM definitions of ADHD do not confine the disorder solely to childhood and in fact many adults are also diagnosed with Adult Attention Deficit Disorder (AADD), which is simply the common label for ADHD in adults. Current theory holds that approximately 30% of children diagnosed retain the disorder as adults. Although the disorder may not have been diagnosed in an indidivual during childhood, it is also currently thought that all adults with the disorder had it in childhood.

Professionals have noted that adults with ADD/ADHD have often developed more coping skills than children, which make symptoms less noticeable to themselves and others.

See Also

References

  • Understanding ADD by Dr Christopher Green & Dr Kit Chee, ISBN 0-86824-587-9, Doubleday 1994
  • The ADHD-Autism Connection: A Step toward more accurate diagnosis and effective treatment, by Diane M. Kennedy, ISBN 1578564980 (The aim of this book is to explore the similarities that attention deficit hyperactivity disorder (ADHD) shares with a spectrum of disorders currently known as pervasive developmental disorders.)
  • Hartmann, Thom. (1998) Healing ADD: Simple Exercises That Will Change Your Daily Life. Underwood-Miller (1st ed.) ISBN 1887424377 (Uses Neurolinguistic Programming techniques)
  • Kate Kelly and Peggy Ramundo: You Mean I'm Not Lazy, Stupid, or Crazy?! A Self-Help Book for Adults with Attention Deficit Disorder (1993). ISBN: 0-684-81531-1
  • {{1}} Dr. Timothy E. Wilens, MD Straight Talk about Psychiatric Medications for Kids (Revised Edition--2004). ISBN 1-57230-945-8.
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