Attention-deficit hyperactivity disorder

Attention-Deficit Hyperactivity Disorder (ADHD) is usually considered to be a neurobehavioral^[1] developmental disorder.^[2] It affects about 3-5% of school aged children^[3] with symptoms starting before seven years of age. It is characterized by a persistent pattern of impulsiveness and inattention, with or without a component of hyperactivity.^[4] ADHD occurs twice as commonly in boys as in girls.^[5] ADHD is generally a chronic^[6] disorder with 10 to 40% of individuals diagnosed in childhood continuing to meet diagnostic criteria in adulthood.^[7][8] As they mature, adolescents and adults with ADHD are likely to develop coping mechanisms to compensate for their impairment.^[9]

Though previously regarded as a childhood diagnosis ADHD can continue throughout adulthood.^[10] ADHD has a strong genetic component.^[11]

Methods of treatment usually involve some combination of medications, behavior modifications, life style changes, and counseling. The American Academy of Pediatrics states that stimulant medications and/or behavior therapy are appropriate and generally safe treatments for ADHD.^[12] A 2006 meta analysis however found a lack of data regarding ADHD drug's potential adverse effects,^[13] with very few studies assessing the safety or efficacy of treatments beyond 4 months,^[14] and no randomized controlled trials assess either for periods of usage longer than two years.^[7][15][16] Treatment of pre-school children is not recommended.^[17]

ADHD and its treatment has been considered controversial since the 1970s.^{[18][19][20][21]} The controversies have involved clinicians, teachers, policymakers, parents, and the media with opinions regarding ADHD that range from those who do not believe it exists at all to those who believe that there is genetic and physiological basis for the condition, and also include disagreement about use of stimulant medications in treatment.^[19]

Classification

ADHD is best seen as the extreme of a continuous trait that is found throughout the population. ^[17] ADHD is a developmental disorder where certain traits such as impulse control lag in development when compared to the general population^[22]. Using magnetic resonance imaging, this developmental lag has been estimated to range from 3 to 5 years in the prefrontal cortex.^[23]. These delays are considered to cause impairment. ADHD has also been classified as a behavior disorder. ^[24] A diagnosis of ADHD however does not imply a neurological disease.^[17]

It is classified as a disruptive behavior disorder along with oppositional defiant disorder, conduct disorder, and antisocial disorders.^[25]

Symptoms

The most common symptoms of ADHD are^[26][27]:

• Impulsiveness: acting before thinking of consequences, jumping from one activity to another, disorganization, tendency to interrupt during conversations.^[26]
• Hyperactivity: restlessness, often characterized by an inability to sit still, fidgeting, squirminess, climbing on things, restless sleep.^[26]
• Inattention: easily distracted, zoning out, not finishing work, difficulty listening.^[26]

The DSM IV categorizes the symptoms of ADHD into three clusters, referred to as subtypes: (1) Inattentive; (2) hyperactive/impulsive; and (3) combined^[28]. Most ordinary people exhibit some of these behaviors but not to the point where they significantly interfere with a person's work, relationships, or studies, or it accompanies other disorders, such as anxiety or depression.

Hyperactivity is common among children with ADHD but tends to disappear during adulthood. However, over half of children with ADHD continue to have some 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 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:

• Oppositional defiant disorder (35%) and Conduct disorder (26%). These are both characterized by anti-social behaviors such as stubbornness, aggression, frequent temper tantrums, deceitfulness, lying, or stealing.^[27]
• 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.^[27]
• Bipolar disorder. As many as 25% of children with ADHD have bipolar disorder. Children with this combination may demonstrate more aggression and behavioral problems than those with ADHD alone.^[27]
• Anxiety Disorders. Such disorders commonly accompany ADHD, particularly Obsessive-Compulsive Disorder. OCD is believed to share a genetic component with ADHD, and shares many of its characteristics.^[27]

Although the reasons are not clear, it has long been observed that many children seem to "outgrow" ADHD. These individuals include those both treated and untreated. It is also known that many adolescents and adults develop coping skills as they mature, offsetting impairments.

Causes

A specific cause of ADHD is not known.^[29] It is however felt that it has a strong genetic component, but it can also be caused by various problems, including difficulties with pregnancy, birth, early childhood severe illness, and environmental toxins.^[30]

Genetic factors

Twin studies indicate that the disorder is highly heritable and that genetics cause about 75% of ADHD cases.^[17] Hyperactivity also seems to be primarily a genetic condition however other causes do have an effect.^[31]

Researchers believe that a large majority of ADHD cases arise from a combination of various genes, many of which affect dopamine transporters. Candidate genes include dopamine transporter, dopamine receptor D4, dopamine beta-hydroxylase, monoamine oxidase A, catecholamine-methyl transferase, serotonin transporter promoter (SLC6A4), 5-hydroxytryptamine 2A receptor (5-HT2A), 5-hydroxytryptamine 1B receptor (5-HT1B),^[32] the 10-repeat allele of the DAT1 gene,^[33] the 7-repeat allele of the DRD4 gene,^[33] and the dopamine beta hydroxylase gene (DBH TaqI).^[34]

The broad selection of targets indicates that ADHD does not follow the traditional model of a "genetic disease" and should be viewed as a complex interaction among genetic and environmental factors. Even though all these genes might play a role, to date no single gene has been shown to make a major contribution to ADHD.^[35]

Environmental factors

Twin studies to date have suggested that approximately 9-20 percent of the variance in hyperactive-impulsive-inattentive behavior or ADHD symptoms can be attributed to nonshared environmental (nongenetic) factors.^[36]

Environmental factors implicated include alcohol and tobacco smoke exposure during pregnancy and lead exposure after birth.^[37] The relation of smoking to ADHD could be due to nicotine causing hypoxia (lack of oxygen) in utero. However it could also be that women with ADHD are more likely to smoke and therefore, due to the strong genetic component of ADHD, are more likely to have children with ADHD. Complications during pregnancy and birth—including premature birth—might also play a role.

Current evidence does not support an association between head injuries and ADHD. ^[38]

Diet

Additives

In two studies published in 2004 and 2007, researchers from Southampton University suggested that a statistically significant increase in hyperactive symptoms as well as a decrease in attention span occurred after children had consumed common artificial food colours and additives from fruit drinks.^[39][40] The European Food Safety Authority (EFSA) was asked to review the 2007 study that asserted a link between consumption of artificial food colours and the observation of hyperactive behaviour in children. EFSA invited a number of experts in behaviour, child psychiatry, allergenicity and statistical analysis to provide input to the EFSA Panel on Additives, Flavourings, Processing Aids and Materials in Contact with Food. In a press release ^[41] from March 2008, EFSA indicated that, in their view, the 2007 study provided only limited evidence of an association between the intake of the mixture of additives and activity and attention, and then only in some children studied. They further indicated that the effects reported in the study were not consistent for the two age groups and the two food additive mixtures.

In May, however, the British Medical Journal ran an editorial by professor of paediatric allergy and clinical immunology Andrew Kemp of the University of Sydney, Australia.^[42] Commenting on the reported EFSA rejection of the Southampton study conclusions that there is a link between food additives and hyperactivity, he said that closer analysis of the EFSA report does not support this negative interpretation. He said that after a reanalysis of the data, the EFSA panel concluded that “the study provides limited evidence that the two different mixtures . . . had a small and statistically significant effect on activity and attention.” Kemp further said, "Importantly, the trial examined a cohort of normal (not hyperactive) children, but the findings have obvious implications for children with hyperactivity."

Moreover, said Kemp, meta-analysis^[43] shows that dietary elimination of colourings and preservatives provides a statistically significant benefit. He suggested that "an appropriately supervised and evaluated trial of eliminating colourings and preservatives should be part of standard treatment for individual children."

Meanwhile, in the U.S., the February 2008 issue of the American Academy of Pediatrics (AAP) Grand Rounds had reported on the Southampton study. They concluded that "Although quite complicated, this was a carefully conducted study in which the investigators went to great lengths to eliminate bias and to rigorously measure outcomes." They also said, in discussing results of the study, that "there was a trend for more hyperactive behaviors associated with the food additive drink in virtually every assessment. Thus, the overall findings of the study are clear and require that even we skeptics, who have long doubted parental claims of the effects of various foods on the behavior of their children, admit we might have been wrong."^[44]

So far, the American FDA has continued to ignore both the study and the Grand Rounds article, continuing to quote information from 1982 on their website,^[45] while the UK Food Standards Agency (FSA) in April called for a ban on the use of six artificial colorings in a ruling which recommends that the chemicals be removed from products by 2009.^[46]

Shortly thereafter, in July 2008, the European Union (EU) ruled that synthetic food colorings (also called azo dyes) must be labelled not only with the relevant E number, but also with the words "may have an adverse effect on activity and attention in children."^[47]

Sugar

On the subject of sugar, controlled studies by Behar et al. in 1984, Milich and Pelham in 1986, and Wolraich et al. in 1985, shows that sucrose (sugar) has no effect on behavior. In particular, the Wolraich study found that in addition to not causing ADHD, sugar does not exacerbate the symptoms of children diagnosed as having ADHD. The results of the study even suggested that sugar in fact had a slight calming effect.^[48][49][50]

It may be important to note here that corn syrup and high fructose corn syrup - the sugars actually found in most sweets and sugary foods consumed by children - were not part of any of these studies.

Omega 3

Clinical trials supplementing with Omega 3 fatty acids show a significant reduction of ADHD-related symptoms in a 3 to 6 months period. ^{[51][52][53][54]}

Social factors

There is no compelling evidence that social factors alone can cause ADHD.^[22] Many researchers believe that relationships with caregivers have a profound effect on attentional and self-regulatory abilities. A study of foster children found that a high number of them had symptoms closely resembling ADHD,^[55] while other researchers have found behavior typical of ADHD in children who have suffered violence and emotional abuse.^[56] Furthermore, Complex Post Traumatic Stress Disorder can result in attention problems that can look like ADHD, as can Sensory Integration Disorders.

Alternative theories

Hunter vs. farmer theory of ADHD

Main article: Hunter vs. farmer theory

The hunter vs. farmer theory is a hypothesis proposed by author Thom Hartmann about the origins of attention-deficit hyperactivity disorder (ADHD). He believes that these conditions may be a result of adaptive behavior of the species, his theory states that those with ADHD retained some of the older hunter characteristics.^[57]

Neurodiversity

Main article: Neurodiversity

Proponents of this theory assert that atypical (neurodivergent) neurological development is a normal human difference that is to be tolerated and respected as any other human difference. Social critics argue that while biological factors obviously may play a large role in difficulties with sitting still and/or concentrating on schoolwork in some children, for a variety of reasons the children have failed to integrate the social expectations that others have of them. ^[58]

Social construct theory of ADHD

Main article: Social construct theory of ADHD

Social critics question whether ADHD is wholly or even predominantly a biological illness. A minority of these critics maintain that ADHD was "invented and not discovered". They believe that no disorder exists and that the behaviour observed is not abnormal and can better be explained by environmental causes or just the personality of the "patient."^[17]

Pathophysiology

PET scans measure the activity of various parts of the brain. The image on the right illustrates glucose metabolism in the brain of a person diagnosed with ADHD while doing an assigned task. The image on the left illustrates glucose metabolism in the brain of a normal subject when given that same task. The significance of the research was that the harder a person with ADHD concentrated the less activity was measured. This was the exact opposite for the non ADHD group. However, that was remedied when the ADHD subjects took stimulant medication. These findings are still not definitive.^[59][60]

The pathophysiology of ADHD is unclear and there are a number of competing theories.^[61]

In one study a delay in development of certain brain structures by an average of three years occurred in ADHD elementary school aged patients. The delay was most prominent in the frontal cortex and temporal lobe, which are believed to be responsible for the ability to control and focus thinking. 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 be required for the fidgetiness that characterize an ADHD diagnosis.^[62]

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.^[63]

Additionally, SPECT scans found people with ADHD to have reduced blood circulation (indicating low neural activity),^[64] and a significantly higher concentration of dopamine transporters in the striatum which is in charge of planning ahead. ^[65][66] Medications focused on treating ADHD (such as methylphenidate) work by reducing dopamine reuptake in certain areas of the brain, such as those that control and regulate concentration. As dopamine is a stimulant, this increases neural activity and thus blood flow in these areas (blood flow is a marker for neural activity). 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.^[67]

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.

A 1990 PET scan study found that global cerebral glucose metabolism was 8% lower in medication-naive adults who had been hyperactive since childhood.^[68] 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 hyperactive since childhood when given that same task. The regions with the greatest deficit of activity included the premotor cortex and the superior prefrontal cortex.^[68] Further studies found that chronic stimulant treatment had little effect on global glucose metabolism^[69], while a study in girls failed to find a decreased global glucose metabolism,^[70] and in teenagers PET scans were unable to differentiate normal children from those with ADHD.^[71] The significance of the research by Dr. Alan Zametkin has still not been determined.^[72][73][74]

Diagnosis

No objective test exists to make a diagnosis of ADHD. It thus remains a clinical diagnosis.^[75]

In North America, the DSM-IV criteria are often the basis for a diagnosis while European countries usually use the ICD-10.^[76]

Many of the symptoms of ADHD occur from time to time in everyone; in patients with ADHD, the frequency of these symptoms is greater and significantly impairs their life. This impairment must occur in multiple settings to be classified as ADHD. As with many other psychiatric and medical disorders, the formal diagnosis is made by a qualified professional in the field based on a set number of criteria. In the USA these criteria are laid down by the American Psychiatric Association in their Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), 4th edition. Based on the DSM-IV criteria listed below, three types of ADHD are classified:

1. ADHD, Combined Type: if both criteria 1A and 1B are met for the past 6 months
2. ADHD Predominantly Inattentive Type: if criterion 1A is met but criterion 1B is not met for the past six months
3. ADHD, Predominantly Hyperactive-Impulsive Type: if Criterion 1B is met but Criterion 1A is not met for the past six months.

The previously used term ADD expired with the most recent revision of the DSM. Consequently, ADHD is the current nomenclature used to describe the disorder as one distinct disorder which can manifest itself as being a primary deficit resulting in hyperactivity/impulsivity (ADHD, predominately hyperactive-impulsive type) or inattention (ADHD predominately inattentive type) or both (ADHD combined type).

DSM-IV criteria

I. Either A or B:^[28]

A. Six or more of the following symptoms of inattention have been present for at least 6 months to a point that is disruptive and inappropriate for developmental level:

1. Often does not give close attention to details or makes careless mistakes in schoolwork, work, or other activities.
2. Often has trouble keeping attention on tasks or play activities.
3. Often does not seem to listen when spoken to directly.
4. Often does not follow instructions and fails to finish schoolwork, chores, or duties in the workplace (not due to oppositional behavior or failure to understand instructions).
5. Often has trouble organizing activities.
6. Often avoids, dislikes, or doesn't want to do things that take a lot of mental effort for a long period of time (such as schoolwork or homework).
7. Often loses things needed for tasks and activities (e.g. toys, school assignments, pencils, books, or tools).
8. Is often easily distracted.
9. Often forgetful in daily activities.

B. Six or more of the following symptoms of hyperactivity-impulsivity have been present for at least 6 months to an extent that is disruptive and inappropriate for developmental level:

• Hyperactivity:

1. Often fidgets with hands or feet or squirms in seat.
2. Often gets up from seat when remaining in seat is expected.
3. Often runs about or climbs when and where it is not appropriate (adolescents or adults may feel very restless).
4. Often has trouble playing or enjoying leisure activities quietly.
5. Is often "on the go" or often acts as if "driven by a motor".
6. Often talks excessively.

• Impulsiveness:

1. Often blurts out answers before questions have been finished.
2. Often has trouble waiting one's turn.
3. Often interrupts or intrudes on others (e.g., butts into conversations or games).

II. Some symptoms that cause impairment were present before age 7 years.

III. Some impairment from the symptoms is present in two or more settings (e.g. at school/work and at home).

IV. There must be clear evidence of significant impairment in social, school, or work functioning.

V. The symptoms do not happen only during the course of a Pervasive Developmental Disorder, Schizophrenia, or other Psychotic Disorder. The symptoms are not better accounted for by another mental disorder (e.g. Mood Disorder, Anxiety Disorder, Dissociative Disorder, or a Personality Disorder).

ICD-10

In the tenth edition of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) the symptoms of ADHD are given the name "Hyperkinetic disorders". When a conduct disorder (as defined by ICD-10^[77]) is present, the condition is referred to as "Hyperkinetic conduct disorder". Otherwise the disorder is classified as "Disturbance of Activity and Attention", "Other Hyperkinetic Disorders" or "Hyperkinetic Disorders, Unspecified". The latter is sometimes referred to as, "Hyperkinetic Syndrome".^[77]

Other diagnostic guidelines

The American Academy of Pediatrics Clinical Practice Guideline for children with ADHD emphasizes that a reliable diagnosis is dependent upon the fulfillment of three criteria:^[78]

• The use of explicit criteria for the diagnosis using the DSM-IV-TR.
• The importance of obtaining information about the child’s symptoms in more than one setting.
• The search for coexisting conditions that may make the diagnosis more difficult or complicate treatment planning.

All three criteria are determined using the patient's history given by the parents, teachers and/or the patient.

The Centers for Disease Control and Prevention (CDC) state that a diagnosis of ADHD should only be made by trained health care providers, as many of the symptoms may also be part of other conditions, such as bodily illness or other physiological disorders, such as hypothyroidism. It is not uncommon that physically and mentally nonpathological individuals exhibit at least some of the symptoms from time to time. Severity and pervasiveness of the symptoms leading to prominent functional impairment across different settings (school, work, social relationships) are major factors in a positive diagnosis.

Adults often continue to be impaired by ADHD. Adults with ADHD are diagnosed under the same criteria, including the stipulation that their symptoms must have been present prior to the age of seven.^[79] Adults face some of their greatest challenges in the areas of self-control and self-motivation, as well as executive functioning, usually having more symptoms of inattention and fewer of hyperactivity or impulsiveness than children do.^[80]

Common comorbid conditions are Oppositional Defiance Disorder (ODD). About 20% to 25% of children with ADD meet criteria for a learning disorder.^[81] Learning disorders are more common when there are inattention symptoms.^[82]

Differential diagnoses

To confer ADHD as the most likely diagnosis, other potential diagnoses must be considered.

Management

Main article: Attention-deficit hyperactivity disorder management

Methods of treatment often involve some combination of medications, behavior modifications, life style changes, and counseling.

Behavioral interventions

Many believe that concepts such as, self-regulation, self-monitoring, and effortful control are at the center of the functional impairments regarding ADHD. There are Cognitive-Behavioral interventions designed to improve these areas and boost self-efficacy, social competence, and emotional control, which can affect attention and self-regulation. One such program is the Challenge Software Program. This program uses media in the form of interactive videos and games to grab and hold an inattentive child's attention and engage them in the process quickly. The program also offers measurable Pre and Post outcomes to illustrate improvement.

Family therapy has shown little benefit in the treatment of ADHD.^[83] Education to help parents understand ADHD has shown short term benefits.^[84]

Pharmacological treatment

Stimulant medications are the most clinically and cost effective method of treating ADHD. ^[84][85] A recent meta analysis of randomized controlled trials has found that the use of stimulants improve teachers' and parents' ratings of disruptive behavior; however they do not improve academic achievement.^[7] Stimulants neither increase nor decrease rates of delinquency or substance abuse at 3 years.^[7] No significant differences between the various drugs in terms of efficacy or side effects has been found.^[86][87] About 70% of children improve after being treated with stimulants.^[88] Medications, however, are not recommended for pre-school children with ADHD.^[89]Stimulants, in the short term, have been found to be safe in the appropriately selected patient and appear well tolerated over 5 years of treatment.^[90]

Long term safety, however, has not been determined. There are no randomized controlled trials assessing the harms or benefits of treatment beyond two years.^[7] The American Heart Association and the American Academy of Pediatrics feels that it is prudent to carefully assess children for heart conditions before treating them with stimulant medications.^[91] The FDA has added black box warning to some ADHD medications.^[92] Amphetamines ( Adderall ) have warnings about potential for abuse, drug dependence, and sudden death.^[93]

A recent review states that ADHD studies “have major methodological deficiencies which are compounded by their restriction to school-age children, relatively short follow - up, and few data on adverse effects.” ^[94]

Comorbid disorders or substance abuse can make the diagnosis and the treatment of ADHD more difficult. Psychosocial therapy is useful in treating some comorbid conditions.^[95]

Support groups

In the UK, the Hyperactive Children's Support Group (HACSG) ^[96] is a registered charity which aims to help ADHD/Hyperactive children and their families. The HACSG is a proponent of a dietary approach to the problem of hyperactivity.

In the US, there are a number of support groups, including:

• Attention Deficit Disorder Association (ADDA)
• Children and Adults with Attention Deficit Disorder (CHADD)
• Feingold Association of the United States (FAUS)
• Learning Disabilities Association of America (LDA)

Prognosis

ADHD diagnosed in childhood resolves in 40 to 90% of individuals by the time they reach adulthood.^[7][97] Those affected are likely to develop coping mechanisms as they mature thus compensating for their previous ADHD. ^[98]

37% of those with ADHD do not get a high school diploma even though many of them will receive special education services.^[22] The combined outcomes of the expulsion and dropout rates indicate that almost half of all ADHD students never finish high school.^[99] In the United States, less than 5% of individuals with ADHD get a college degree^[100] compared to 28% of the general population.^[101]

People with ADHD tend to work better in less structured environments with fewer rules. Self-employment or jobs with greater autonomy are generally well suited for them. Hyperactive types are likely to change jobs often due to their constant need for new interests and stimulations to keep motivated. Recent studies suggest that many expatriates have the 7-repeat allele of DRD4 causing ADHD.

Epidemiology

ADHD's global prevalence is estimated at 3-5% in people under the age of 19. There is however both geographical and local variability among studies. Geographically children in North America appearing to have a higher rate of ADHD than children in Africa and the Middle East,^[3] well published studies have found rates of ADHD as low as 2% and as high as 14% among school aged children.^[102] The frequency of the diagnosis of ADHD differs betwen male children (10%) and female children (4%) in the United States.^[103]. This difference between genders may reflect either a difference in susceptibility or that females with ADHD are less likely to be diagnosed than males.^[104][105]

Rates of ADHD diagnosis and treatment have increased in both the UK and the USA since the 1970s. In the UK an estimated 0.5 per 1,000 children had ADHD in the 1970s well 3 per 1,000 received ADHD medications in the late 1990s. In the USA in the 1970s 12 per 1,000 had the diagnosis well in the late 1990s 34 per 1,000 had the diagnosis and the numbers continue to increase.^[17]

History

Terminology

It may be helpful to understand that "ADD" and "ADHD" are the same thing, and constitute a single syndrome, with several important and distinctive variations. The clinical definition of "ADHD" dates to the mid-20th century, but was known by other names. Physicians developed a diagnosis for a set of conditions variously referred to as "minimal brain damage", "minimal brain dysfunction", "learning/behavioural disabilities" and "hyperactivity". Some of these labels became problematic as knowledge expanded. For example, as awareness grew that many children with no indication of brain damage also displayed the syndrome, the label which included the words "brain damage" didn't seem appropriate.

The DSM-II (1968) began to call it "Hyperkinetic Reaction of Childhood" even though the professionals were aware that many of the children so diagnosed exhibited attention deficits without any signs of hyperactivity. In 1980, the DSM-III introduced "ADD (Attention-Deficit Disorder) with or without hyperactivity." That terminology (ADD) technically expired with the revision in 1987 to ADHD in the DSM-III-R. In the DSM-IV, published in 1994, ADHD with sub-types was presented. The current version (as of 2008), the DSM-IV-TR was released in 2000, primarily to correct factual errors and make changes to reflect recent research; ADHD was largely unchanged.^[106]

Under the DSM-IV, within the ADHD syndrome, there are three sub-types, including one which lacks the hyperactivity component.^[107] Approximately one-third of people with ADHD have the predominantly inattentive type (ADHD-I), meaning that they do not have the hyperactive or overactive behavior components of the other ADHD subtypes.

Even today, the ADHD terminology is objectionable to many. There is some preference for using the ADHD-I, ADD, and AADD terminology when describing individuals lacking the hyperactivity component, especially among older adolescents and adults who find the term "hyperactive" inaccurate, inappropriate and even derogatory.

18th century

In 1798, a Scottish-born physician and author, Sir Alexander Crichton (1763–1856), described what seems to be a mental state much like the inattentive subtype of ADHD, in his book An inquiry into the nature and origin of mental derangement: comprehending a concise system of the physiology and pathology of the human mind and a history of the passions and their effects. In the chapter "Attention", Crichton described a "mental restlessness".^[108][109]

"The incapacity of attending with a necessary degree of constancy to any one object, almost always arises from an unnatural or morbid sensibility of the nerves, by which means this faculty is incessantly withdrawn from one impression to another. It may be either born with a person, or it may be the effect of accidental diseases.

"When born with a person it becomes evident at a very early period of life, and has a very bad effect, inasmuch as it renders him incapable of attending with constancy to any one object of education. But it seldom is in so great a degree as totally to impede all instruction; and what is very fortunate, it is generally diminished with age."^[110]

Dr. Crichton further observed: "In this disease of attention, if it can with propriety be called so, every impression seems to agitate the person, and gives him or her an unnatural degree of mental restlessness. People walking up and down the room, a slight noise in the same, the moving of a table, the shutting a door suddenly, a slight excess of heat or of cold, too much light, or too little light, all destroy constant attention in such patients, inasmuch as it is easily excited by every impression."^[111]

Crichton has noted that "they have a particular name for the state of their nerves, which is expressive enough of their feelings. They say they have the fidgets".^[112] Dr. Crichton suggested that these children needed special educational intervention and noted that it was obvious that they had a problem attending even how hard they did try. "Every public teacher must have observed that there are many to whom the dryness and difficulties of the Latin and Greek grammars are so disgusting that neither the terrors of the rod, nor the indulgence of kind intreaty can cause them to give their attention to them."^[113]

Alexander Crichton was almost two centuries ahead of his time in his observations of what is now known as the Inattention subtype of ADHD. He wrote about the salient features of this disorder, including attentional problems, restlessness, early onset, and how it can affect schooling, without any of the moralism introduced by George Still and later authors.^[114][115]

20th century

On 4th, 6th and 11th March 1902, the father of British pediatrics Sir George Frederick Still (1868–1941) gave a series of lectures to the Royal College of Physicians in London under the name “Goulstonian lectures” on ‘some abnormal psychical conditions in children’, which were published later the same year in the Lancet.^[116]

He described 43 children who had serious problems with sustained attention and self-regulation, who were often aggressive, defiant, resistant to discipline, excessively emotional or passionate, which showed little inhibitory volition, had serious problems with sustained attention and could not learn from the consequences of their actions; though their intellect was normal. He wrote “I would point out that a notable feature in many of these cases of moral defect without general impairment of intellect is a quite abnormal incapacity for sustained attention.^[117]

Dr. Still wrote: “there is a defect of moral consciousness which cannot be accounted for by any fault of environment” When Still was talking about Moral Control, he was referring to it as William James had done before him, but to Still, the moral control of behavior meant “the control of action in conformity with the idea of the good of all” ^[118]

"Another boy, aged 6 years, with marked moral defect was unable to keep his attention even to a game for more than a very short time, and as might be expected, the failure of attention was very noticeable at school, with the result that in some cases the child was backward in school attainments, although in manner and ordinary conversation he appeared as bright and intelligent as any child could be."^[119] He proposed a biological predisposition to this behavioral condition that was probably hereditary in some children and the result of pre- or postnatal injury in others. ^{[120] [121]}

George Still certainly did not use the current terminology for this disorder, but many historians of ADHD have inferred that the children he described in his series of three published lectures to the Royal College of Physicians would likely have qualified for the current disorder of ADHD combined type, among other disorders. ^{[122][123] [124]}

Encephalitis epidemic 1917–1918

The treatment of children with similar behavioral problems who had survived the epidemic of encephalitis lethargica from 1917 to 1918 and the pandemic of influenza from 1919 to 1920 led to terminology which referred to "brain damage." ^[125]

Adult ADHD

Main article: Adult attention-deficit disorder

In the 1970s researchers began to realize that the condition now known as ADHD did not always disappear in adolescence, as was once thought. At about the same time, some of the symptoms were also noted in many parents of the children under treatment. The condition was formally recognized as afflicting adults in 1978, often informally called adult ADD, since symptoms associated with hyperactivity are generally less pronounced.

It has been estimated that about eight million adults have ADHD in the United States.^[126] Untreated adults with ADHD often have chaotic life-styles, may appear to be disorganized, and may rely on non-prescribed drugs and alcohol to get by. They often have such associated psychiatric comorbidities as depression, anxiety, bipolar disorder, substance abuse, or a learning disability.^[127] In 2004, noted researchers estimated the yearly income loss for adults with ADHD in the United States as $77 billion. This may be partially because it is also estimated that only 15% of adults in the U.S. with ADHD are aware that they have the disorder, although many adults struggle with it.^[128]

A diagnosis of ADHD may offer adults insight into their behaviors and allow patients to become more aware and seek help with coping and treatment strategies.^[129] Studies show that adult ADHD is treated successfully with a combination of medication and behavior therapy.^[130] A mature patient, moreso than a child, may be able to provide feedback and help self-direct the process.

Many professionals have speculated that in the next DSM (tentatively DSM-V), ADHD in adults may be differentiated from the syndrome as it occurs in children.^[131] Only recognized as occurring in adults in 1978, it is currently not addressed separately. Obstacles that clinicians face when assessing adults who may have ADHD include developmentally inappropriate diagnostic criteria, age-related changes, comorbidities, and the possibility that high intelligence or situational factors can mask ADHD symptoms.^[132]

Society and Culture

ADHD has been found across the world when DSM-IV criteria are used in diagnosis.^[133] The DSM-IV estimates that 3%-7% of children suffer from ADHD. Some studies have estimated higher rates in community samples, and ADHD is diagnosed 2 - 4 times more often in boys than in girls.^[134][135] The core impairments are expressed in different cultural contexts^[136] although there is disagreement about this observation.^[137] ADHD is considered differently based on how those who have an interest in the topic approach the subject. They can use descriptors used in the DSM4. They can frame the issue on a biological basis verse character flaws. Others see relief and hope in identifying and labeling a real problem.^[138]

The media has reported on many issues related to ADHD. In 2001 PBS's Frontline ran a five-part TV series entitled "Medicating kids" which was specifically about ADHD.^[139] The program included a selection of interviews with representatives of various points of view. In one segment, entitled backlash, retired neurologist Fred Baughman and Peter Breggin who PBS described as "outspoken critics who insist [ADHD is] a fraud perpetrated by the psychiatric and pharmaceutical industries on families anxious to understand their children's behavior,"^[140] were interviewed on the legitimacy of the disorder. Russell Barkley and Xavier Castellanos, then head of ADHD research at the National Institute of Mental Health (NIMH), defended the viability of the disorder. In Castellanos's interview he stated how little is scientifically understood.^[141] Lawrence Diller was interviewed on the business of ADHD along with a representative from Shire Plc.

A number of notable individuals have given controversial opinions on ADHD. Scientologist Tom Cruise's interview with Matt Lauer was widely watched by the public. In this interview he spoke about postpartum depression and also referred to Ritalin and Adderall as being "street drugs" rather than as ADHD medication. In England Baroness Susan Greenfield, a leading neuroscientist,^[142] spoke out publicly about the need for a wide-ranging inquiry in the House of Lords into the dramatic increase in the diagnosis of ADHD in the UK and possible causes^[143] following a 2007 BBC Panorama programme which highlighted US research (The Multimodal Treatment Study of Children with ADHD by the University of Buffalo showing treatment results of 600) suggesting drugs are no better than therapy for ADHD in the long-term.

Controversies

Main article: Attention-deficit hyperactivity disorder controversies

Attention-deficit hyperactivity disorder (ADHD) is a highly controversial psychiatric disorder despite being a well validated clinical diagnosis.^[144][145] Controversies involving clinicians, teachers, policymakers, parents, and the media with opinions regarding ADHD range from those who do not believe it exists at all to those who believe that there is genetic and physiological basis for the condition.^[146]

Researchers from McMaster identified five features of ADHD that contribute to its controversial nature: 1) it is a clinical diagnosis for which there are no laboratory or radiological confirmatory tests or specific physical features; 2) diagnostic criteria have changed frequently; 3) there is no curative treatment, so long-term therapies are required; 4) therapy often includes stimulant drugs that are thought to have abuse potential; and 5) the rates of diagnosis and of treatment substantially differ across countries.^[147]

The British Psychological Society states that: “The idea that children who don’t attend or who don’t sit still in school have a mental disorder is not entertained by most British clinicians.”^[148]

Hearings were held in the US Congress. A series of lawsuits culminating with the failed Ritalin class action lawsuits were in the courts. Antipsychiatry critics such as Peter Breggin and Fred Baughman received a lot of press coverage culminating in PBS's Frontline which ran a five-part TV series entitled "Medicating kids".^[149] This timing also coincided with a dramatic increase in the use of stimulant medication which since has leveled off. In the UK medication use is increasing dramatically. Susan Greenfield, a leading neuroscientist,^[150] wanted a wide-ranging inquiry in the House of Lords into the dramatic increase in the diagnosis of ADHD in the UK and possible causes^[151] following a 2007 BBC Panorama programme which highlighted US research (The Multimodal Treatment Study of Children with ADHD by the University of Buffalo showing treatment results of 600) suggesting drugs are no better than therapy for ADHD in treating behaviour symptoms. Opinions regarding ADHD range from those who do not believe it exists to those who believe that there is genetic and physiological basis for the condition.^[152]

In the Harvard Review of Psychiatry, three authors from Departments of Political Science and Psychology at the University of California campuses in Richmond and Berkeley stated "ADHD is one of the most controversial psychiatric disorders, in part because it is also the most commonly diagnosed mental disorder among minors."^[153] There is concern about the effects of an ADHD diagnosis on the mental state and self-esteem of patients.^[154][155] There is disagreement over the cause of ADHD and there are questions about research methodologies ^[156], and skepticism toward its classification as a mental disorder.^[154] Social critics point to changing standards of diagnosis, reflected, for example, in the more careful set of standards issued in 2000 by the American Academy of Pediatrics (AAP) as an aid to clinicians, intended to supplement DSM-IV.^[157]

Concern exists that "elevated but still developmentally normal levels of motor activity, impulsiveness, or inattention" traits of childhood could be inappropriately interpreted as ADHD.^{[158] [159]} The National Institute of Mental Health states that, "stimulant drugs, when used with medical supervision, are usually considered quite safe."^[160] Some parents and professionals have raised questions about the side effects of drugs and their long term use.^[161] Calls for greater scrutiny are made by some news sources, social critics, religions, and medical professionals. Ethical and legal issues with regard to treatment have been key areas of concern for these critics.

See also

References

Further reading

External links

• Attention-Deficit / Hyperactivity Disorder (ADHD) at the Center for Disease Control
• The Challenge Software Program - Interactive Web-based Intervention for Children
• Diagnosis and Treatment of Attention Deficit Hyperactivity Disorder at NIH
• National Institute of Mental Health on ADHD
• "CG72 Attention deficit hyperactivity disorder (ADHD): full guideline" (PDF). NHS (24 September 2008). Retrieved on 2008-10-08.
• Today Show segment on adult ADHD, June 5, 2008
• Patient Voices: A.D.H.D , NYTimes.com