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Attention-deficit disorder with hyperactiv­ity is the single most common problem of children brought to psychologists. It affects about 6% of children, if using the DSM criteria, and it is diagnosed three times more often in boys than girls.

ADHD is attention deficit disorder with hyperactivity. Three sub-types are defined in DSM-5: inattention alone, hyperactivity alone, or the combined syndrome.

ADHD runs in families. Close relatives of those with ADHD have two to eight times greater risk of being diagnosed with the same condition. Twin studies show high heritability for ADHD, between 71%-90% (Thapar, Cooper, Eyre, and Langley, 2012).

ADHD is not classified as a learning disability despite the fact that it can greatly handicap a student at school. Learning disorders are highly selective, affecting particular types of learning. ADHD is a less selective.

A person with a learning disability may do perfectly well in all areas of school except one (math, music, reading). With ADHD, the disorder seems to involve the act of focusing itself.

ADHD is characterized by inattention and hyperactivity or impulsivity. DSM-5 defines clusters of symptoms. Inattention is diagnosed by six or more of the following symptoms:

Often fails to give close attention to details or makes careless mistakes

Often has trouble holding attention on tasks or play activities

Often does not seem to listen when spoken to directly

Often does not follow through on instructions and fails to finish schoolwork, chores, or duties

Often has trouble organizing tasks and activities

Often avoids, dislikes, or is reluctant to do tasks that require mental effort over a long period of time (such as schoolwork or homework).

Often loses things necessary for tasks and activities (e.g. school materials, pencils, books, tools, wallets, keys, paperwork, eyeglasses, mobile telephones).

Is often easily distracted

Is often forgetful in daily activities.

Hyperactivity or impulsivity is defined by six or more of the following symptoms:

Often fidgets with or taps hands or feet, or squirms in seat

Often leaves seat in situations when remaining seated is expected

Often runs about or climbs in situations where it is not appropriate (or "feeling restless" in adults)

Often unable to play or take part in leisure activities quietly

Is often "on the go" acting as if "driven by a motor".

Often talks excessively

Often blurts out an answer before a question has been completed

Often has trouble waiting his/her turn

Often interrupts or intrudes on others (e.g., butts into conversations or games)

What are typical symptoms of ADHD?

The symptoms must be present before age 12 to qualify as ADHD by the DSM criteria. Also, the symptoms must be present in two or more settings: home, school, or work (so inattention at school alone is not diagnostic of ADHD).

As usual for psychiatric disorders, the difficulties must be severe enough to interfere with normal life. There must not be another mental disorder that could explain the symptoms.

Here is a typical case history of a child diagnosed as having attention deficit/hyperactivity disorder (ADHD), from Schwartz and Johnson (1985).

Stanley was referred to a clinical child psychologist at the request of his teacher who, in her own words, "had enough." At 7 years of age, Stan required almost constant supervision to keep him from disturbing other children in his class.

The teacher says that Stan is unable to concentrate on schoolwork for more than a few minutes at a time and seems always to be moving. Even when in his seat, he fidgets around enough to disturb his neighbors.

Stan's mother reports that he is very active at home as well. He never seems to stick to any task for any length of time.

Stan's mother also indicates that his judgment is very poor. He often wanders off without saying where he is going, frequently fails to return home at the proper time, and cannot be relied upon to complete his chores (or any other task).

Stan has an older and younger brother but is unable to play with them because he will not stick to the rules of a game or concentrate for very long periods. Stan intrudes into conversations and games and seems unable to inhibit his impulses. He also has temper tantrums that come and go rapidly.

During the psychological assess­ment, Stan was able to maintain his seat but not his attention. He gave up on the IQ test task easily and frequently changed whatever conver­sational subject the examiner intro­duced. Although he admitted that he was not doing well in school, he did not feel that his behavior was responsible. (Schwartz and Johnson, 1985, p. 164)

As with autism, diagnoses of ADHD have gone up over time, including a 41% rise between 2003 and 2013. This led researchers to wonder if the prevalence is increasing or people were becoming sensitized to the disorder and diagnos­ing it more often for that reason.

After surveying thirty years worth of research, Polancyzk, Willcutt, Salum, Keiling, and Rohde (2014) drew a firm conclusion. "There has been no evidence to suggest an increase in the number of children in the community who meet criteria for ADHD when standardized diagnostic procedures are followed."

Is ADHD becoming more common or simply being diagnosed more often?

In the 1960s, researchers discovered that amphetamines, stimulant drugs, had an unexpected or paradoxical effect upon such children. It slowed them down, made them able to concentrate, and sometimes dramatically alleviated their behavioral problems.

However, amphetamines are addictive, and people need larger and larger doses to get the same effect. Amphetamines also produced some bad side-effects, especially as dosages increased. For these reasons, doctors turned to a chemical relative of the amphetamines, Ritalin, which had fewer side-effects.

What was the paradoxical effect of amphetamines on hyperactive children? Why was Ritalin preferred? What is currently the most common drugs used with ADHD?

Ritalin occasionally worked wonders with hyperactive children. Parents immediate­ly noticed a difference. Suddenly the child took an interest in schoolwork, followed rules, and got along with others.

Ritalin therapy for hyperactive children became more frequent, and this led to some criticisms. CHADD, a national association for parents of children with ADD, was revealed to be taking large amounts of money from the manufac­turer of Ritalin.

CHADD became well known for telling parents that Ritalin was a necessary adjustment for many children, "just like getting glasses if you are nearsighted." By the 1990s, in some schools, "just about every little boy was on Ritalin," according to a 1995 PBS Frontline documentary titled ADD: A Dubious Diagnosis.

Eventually stories of "Ritalin abuse" began to surface. Some students began giving the tablets to friends, and the drug started to be used recreation­ally by teenagers.

Numbers of Ritalin prescriptions dropped somewhat after negative publicity and after a new drug, Adderall, became commonly prescribed for ADHD. Both are chemically related to amphetamines but less addictive and with fewer side effects.

Adderall is much like the so-called "smart drugs" discussed in Chapter 3. As noted there, one consequence of widespread Adderall and Ritalin prescriptions is "dependency among workers in the 25-to-45 age group" on these stimulants, with some feeling they cannot get work done without them.

Stimulant drugs do make a difference in performance. This essay was turned in by a college student taking introductory psychology:

Recently I was diagnosed with ADD (attention deficit disorder). All through high school I struggled with my grades. I just didn't seem to have any "book sense," although I had more common sense than you might imagine.

Then I came to college where I found it very difficult to make my grades. I was put on academic probation for 3 quarters, and I struggled to bring my GPA up.

My mother finally suggested that I had Attention Deficit Disorder because I would study all the time but I didn't seem to comprehend anything. My brain seemed to wander off and think of more enjoyable things, instead of my studies.

Finally I was diagnosed as ADD and saw a doctor about it. The doctor prescribed a small dose of a drug called Ritalin, which stimulates some part of the brain that helps you concentrate. During the first week I took this medicine, not knowing what to expect, I found my ability to study seemed to be improving.

I went to the library, sat down at 6:30 p.m. and found myself still in the library 4 or 5 hours later, hardly noticing that time had passed. I was astonished that I could study so long at one sitting. The medicine seemed to help me get into what I was reading and better comprehend the material. [Author's files]

ADD is also diagnosed in adults, although some clinicians feel that it is not the same disorder as seen in childhood. In adults, people with a diagnosis of ADD fall on the far end of a normal distribution of ADD traits.

In other words, if you measure traits that define ADHD, like impulsivity, some adults are on the extreme end of a bell-shaped curve. The 3% of adults receiving a diagnosis of ADD in the U.S. are on the "tail" of the curve, with the most inattentiveness or hyper­activity.

By contrast, children with ADHD are "outliers" (quite distinct from the main population). If normal children without ADHD fall on a bell-shaped curve of symptoms, those diagnosed with ADHD are way outside the curve, forming a separate clump.

Why do some clinicians suspect that adult ADD is a different disorder than childhood ADHD?

For years, ADHD was considered to be a developmental disorder, implying that childhood ADHD would become adult ADHD. This was inferred from the fact that about 6% of children have ADHD and about 3% of adults have similar symptoms. It was assumed that the 3% of adults were left over from the population that started with ADHD as children. But that may not be the case.

One of the first prospective studies of ADHD, following the same individuals from childhood forward, was carried out in New Zealand. The researchers followed a group of over a thousand randomly chosen New Zealand children from childhood to adulthood (Moffett et al, 2015). They reported the results:

As expected, childhood ADHD had a prevalence of 6% (predominantly male)... Also as expected, adult ADHD had a prevalence of 3% (gender balanced) and was associated with adult substance dependence, adult life impairment, and treatment contact.

Unexpectedly, the childhood ADHD and adult ADHD groups comprised virtually non-overlapping sets; 90% of adult ADHD cases lacked a history of childhood ADHD.

In this group, ADHD did not appear to be a "childhood-onset neurodevelopmental disorder." The people with adult ADHD were mostly not the same people who had childhood ADHD.

The implication is that childhood ADHD did not turn into adult ADHD. Most children with ADHD eventually lost their symptoms, and a different set of people presented the symptoms of ADD in adulthood.

Different results were reported by the Massachusetts General Hospital (MGH) Longitudinal Studies of ADHD in the United States. This research started with psychiatric referrals from the psycho­pharmacology clinic at the hospital, so the group already had a diagnosis of ADHD when the research started.

The researchers followed 208 partici­pants with ADHD (112 boys and 96 girls). The mean age at follow-up was 22 years. 35% of the children still had the full ADHD syndrome at age 22, and another 30% had symptoms but were below the threshold for ADD diagnosis in adult­hood.

Predictors of continuing ADHD included co-morbidity (having other diagnoses such as anxiety disorders), familiality (having ADHD "run in the family") and psychosocial adversity (hard times and stress). The researchers said their study also showed that "ADHD significantly increases the risk for all substances of abuse" including nicotine, drugs, and alcohol.

In the Massachusetts research, many of the children received "lifetime stimulant therapy." Those patients were far less likely to repeat grades, display conduct disorders, or be diagnosed with anxiety disorders as they got older.

The researchers said that lifetime stimulant therapy did not encourage the ADHD group to engage in substance abuse disorders. In fact, the group receiving lifetime stimulant therapy was less likely to take up tobacco smoking. In the Massachusetts sample, tobacco was found to be a "gateway drug" to alcohol and other forms of drug abuse.

What accounts for the difference between the two prospective studies? The populations were different, with many more "at-risk" children in the Massachusetts group, subject to stressors like poverty, broken families, and educational problems.

A measurement effect is also possible. The Massachusetts group was diag­nosed with ADHD in childhood and contacted repeatedly until age 22.

The New Zealand group was a random sample of children. ADHD symptoms were measured along with numerous other variables. Researchers gathering the data later from 22 year olds were not expecting to find symptoms of any particular disorder.

By contrast, the Massachusetts group received a psychia­tric diagnosis in childhood. The diagnosis would have been very credible, occurring in a hospital clinic.

The children were then reminded of their diagnosis as they were contacted for interviews about their educational difficulties and drug abuse periodically over fifteen years. This might well have encouraged negative self-perceptions and low expectations.


Moffett, T. E. et al. [15 more authors] (2015) Is adult ADHD a childhood-onset neurodevelopmental disorder? Evidence from a four-decade longitudinal cohort study. American Journal of Psychiatry, 172, 967-977. Retrieved from:

Polancyzk, G. V., Willcutt, E. G., Salum, G. A., Keiling, C., & Rohde, L. A. (2014) ADHD prevalence estimates across three decades: an updated systematic review and meta-regression analysis. International Journal of Epidemiology, 43, 434-442.

Schwartz, S. & Johnson, J.H. (1985) Psychopathology of Childhood. (2nd Edition). New York: Pergamon Press.

Thapar, A., Cooper, M., Eyre, O., & Langley, K. (2012) Practitioner review: What have we learned about causes of ADHD? Journal of Child Psychology and Psychiatry, 54, 3-16. doi:10.1111/j.1469-7610.2012.02611.x

Uchida, M., Spender, T. J., Faraone, S. V., & Biederman, J. (2015) Adult outcome of ADHD: An overview of results from the MGH longitudinal family studies... Journal of Attention Disorders, 20 1-15. Retrieved from:

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