How well defined is ADD/ADHD?

Question

I understand ADHD is a standard term, but I'm still a bit suspicious that it's not a useful one; Psychiatry doesn't seem like the most reliable field.

Are there good reasons for picking out the behaviors associated with ADHD and giving them a name?

Potential answers

• Behaviors associated with ADHD strongly cluster
• Analyzing questionnaires of attention and focus behaviors with factor analysis naturally produces an 'ADHD dimension' that explains a lot of variance (similar methodology to identifying Big 5 personality traits).
• ADHD diagnosis is a strong independent predictor of something interesting: income or grades or some contrived but interesting lab test (controlling for obvious things like IQ)
• Something else along these lines.

Answer 1

Like all psychiatric disorers, ADD and ADHD are diagnosed using a set of criteria listed in the Diagnostic and Statistical Manual of Mental Disorders, or DSM

The latest version is the DSM-IV-TR. The DSM-V is due out in 2013 and may change these criteria.

Diagnosis is expected to be done by a licensed professional who is able to assess these criteria.

From http://www.mental-health-today.com/add/dsm.htm :

INATTENTION
(need 6 of 9)

- often fails to give close attention to details or makes careless mistakes in schoolwork, work or other activities
- often has difficulty sustaining attention in 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 in the workplace (no if oppositional behavior or doesn’t understand instructions)
- often has difficulty organizing tasks and activities
- often avoids, dislikes, or is reluctant to engage in tasks or activities that require sustained mental effort (such as schoolwork or homework)
- often loses things necessary for tasks or activities (e.g., toys, school assignments, pencils, books, or tools)
- often easily distracted by extraneous stimuli
- often forgetful in daily activities

HYPERACTIVITY-IMPULSIVITY  
(need 6 of 9)

- often fidgets with hands or feet or squirms in seat
- often leaves seat in classroom or in other situations in which remaining seated is expected
- often runs about or climbs excessively in situations in which it is inappropriate (in adolescents or adults, may be limited to subjective feelings of restlessness)
- often has difficulty playing or engaging in leisure activities quietly
- is often "on the go" or often acts as if "driven by a motor"
- often talks excessively
- often blurts out answers before questions have been completed
- often has difficulty awaiting turn
- often interrupts or intrudes on others (e.g., butts into conversations or games)

REQUIREMENTS

- Present at least 6 months, maladaptive and inconsistent with development level
- Some symptoms that caused impairment were present before age 7
- Some impairment from the symptoms is present in two or more settings (e.g., at school {or work} and at home)
- There must be clear evidence of clinically significant impairment in social, academic or occupational functioning

Answer 2

Why the symptoms were picked out and given a name

Professionals used to believe ADHD was something children grew out of, but not anymore. ADHD has always been strongly related to school performance. If a child is not focused on school, and seems unwilling or unable to concentrate, everyone tends to think of ADHD as the cause.

This makes me think that ADHD was "discovered" as an explanation to why some kids are not so good at school. If you look at the symptoms for ADHD, you'll notice that each of them is completely normal behavior, but every one of them reduces performance at school.

Do the symptoms for ADHD cluster?

Yes and no. They cluster in more than 1 cluster. Studying personality psychology, I have noticed a growing number of completely normal personality traits that remind me alot of ADHD.

A stereotypical boy with ADHD (restless, fidgety, takative, forgetful, unorganized) would easily remind you of the MBTI personality type ESxP. (ESFP: http://www.16personalities.com/esfp-personality ESTP: http://www.16personalities.com/estp-personality )

A stereotypical girl with ADHD (silent, daydreaming, inattentive) would remind you of the MBTI personality trait INxP. (INTP: http://www.16personalities.com/intp-personality INFP: http://www.16personalities.com/infp-personality ) Girl's ADHD: http://www.addvance.com/help/women/daydreamer.html

Also note how the "boy's ADHD" and "girl's ADHD" are pretty different. The only common traits are poor attention and organization at school.

The typical ADHD behavior also matches well with several parts of the Big 5:

Substantial effects emerged that were replicated across samples. First, the ADHD symptom cluster of inattention-disorganization was substantially related to low Conscientiousness and, to a lesser extent, Neuroticism. Second, ADHD symptom clusters of hyperactivity-impulsivity and oppositional childhood and adult behaviors were associated with low Agreeableness.

http://psych.colorado.edu/~willcutt/pdfs/nigg_2002.pdf

Although previous research on personality and ADHD has focused primarily on extraversion and neuroticism, the present study found that agreeableness and conscientiousness were stronger predictors. This pattern of results is consistent with the clinical literature on adults with ADHD.

http://www.researchgate.net/profile/James_Parker3/publication/222409991_ADHD_symptoms_and_personality_relationships_with_the_five-factor_model/links/02e7e52cad95c0fcfc000000.pdf

Conscientiousness is what measures your ability to stay focused (and more), and neuroticism measures your patience (and more). And those are exactly what primarily defines the J/P factor in MBTI - and ADHD. You're a P? Congratulations, you may have ADHD. You're a J? Nope, no ADHD there.

Additionally, several of the required symptoms for ADHD do not have any fixed requirement for frequency - they are relative. When each of these symptoms are completely normal at the same time, the whole diagnose becomes relative - Are you too unfocused to function at school, or do you manage to get your homework done despite of poor attention? Because nobody will diagnose you with ADHD as long as you are able to cope and function with school and everyday life. A bit of the problem with the ADHD diagnosis is how there are no exact measurements that can tell whether or not an individual is "suffering".

Having a hard time in everyday life is also one of the requirements to have a diagnosis, but this is more relative than all the other symptoms. Considering how modern societies are increasingly demanding for the individual, and Conscientiousness is -the- strongest predictor for academic success, there is bound to be a growing gap between the most and least successful individuals. The least successful individuals are those who struggle to stay focused, and some of these seek psychological help for it. "You struggle at school because you have trouble staying focused? Here, take this test. Yes, I can see that you have poor attention. You have ADHD"

To put it short: ADHD symptoms are all about academic capability

Answer 3

I understand ADHD is a standard term, but I'm still a bit suspicious that it's not a useful one; Psychiatry doesn't seem like the most reliable field

Okay, I know this is going to sound weird, but I think ADHD is another name for hypofrontality-mediated unfulfilled potential

ADHD as "unfulfilled potential"

Although it is characterised by a dysregulation of executive function, if you look at the diagnostic criteria for ADHD, it's all about a functional impairment. Diagnosis is based on the presence of symptoms, but regardless of the combination of symptoms with which someone presents, it's the following criterion in the DSM-V that's necessary:

There is clear evidence that the symptoms interfere with, or reduce the quality of, so­cial, academic, or occupational functioning.

In other words, one can be performing extremely well academically, have a high IQ, and still have ADHD. This is not to say that individuals with ADHD aren't typically poor-performing, but there's nothing precluding someone from being a high performer and still fulfilling the diagnostic criteria for ADHD:

Is attention deficit hyperactivity disorder a valid diagnosis in the presence of high IQ? Results from the MGH Longitudinal Family Studies of ADHD (Antshel et al., 2007).

Background:  The aim of this study was to assess the validity of diagnosing attention deficit/hyperactivity disorder (ADHD) in high IQ children and to further characterize the clinical features associated with their ADHD.

Methods:  We operationalized giftedness/high IQ as having a full scale IQ ≥120. We identified 92 children with a high IQ who did not have ADHD and 49 children with a high IQ that met diagnostic criteria for ADHD who had participated in the Massachusetts General Hospital Longitudinal Family Studies of ADHD.

Results:  Of our participants with ADHD and a high IQ, the majority (n = 35) met criteria for the Combined subtype. Relative to control participants, children with ADHD and high IQ had a higher prevalence rate of familial ADHD in first‐degree relatives, repeated grades more often, had a poorer performance on the WISC‐III Block Design, had more comorbid psychopathology, and had more functional impairments across a number of domains.

Conclusions:  Children with a high IQ and ADHD showed a pattern of familiality as well as cognitive, psychiatric and behavioral features consistent with the diagnosis of ADHD in children with average IQ. These data suggest that the diagnosis of ADHD is valid among high IQ children.

I note that you won't find any literature on unfulfilled potential. Instead, if you parse the above diagnostic criterion carefully, you'll see it: what precisely does the DSM-5 criterion of "reduced quality of academic functioning" mean but some inability to fulfill one's potential with regards to schooling?

ADHD as hypofrontality

Regarding hypofrontality, this has to do with the view of biological psychiatry that ADHD is mediated by dopaminergic hypofrontality. There is an attempt to map the symptoms to a particular neural substrate.

Fisher & Beckley (1998) is a little old, but characterises the general view:

That is not the end of the whole story. If the brain messengers dopamine and norepinephrine have an impact on the frontal area of the brain, and the hypofrontality creates the higher-level-thinking disorder of ADD or ADHD, then wouldn't it also affect the other thinking areas of the brain that use these same neurotransmitters? Hypofrontality defines the lack of dopamine and norepinephrine primarily in the frontal area of the brain. However, the effect can also be seen in the parietal area of the brain. This defines the basis for the anatomical differences between the two subtypes of ADD: ADHD and ADD without hyperactivity (ADD). It has been found through both clinical research and studies of medication that ADD without hyperactivity is more closely related to the parietal area of the brain and the neurotransmitter nore­pinephrine, while ADHD is found to more related to the frontal area or processes and the neurotransmitter dopamine.

A more recent paper, which refers to the role of D1 dopamine receptors in hypofrontality. However, it focuses more on the role on noradrenaline via a2-adrenoceptors (both dopamine and noradrenaline are catecholamines):

Neurobiology of Executive Functions: Catecholamine Influences on Prefrontal Cortical Functions (Arnsten & Li, 2005)

The prefrontal cortex guides behaviors, thoughts, and feelings using representational knowledge, i.e., working memory. These fundamental cognitive abilities subserve the so-called executive functions: the ability to inhibit inappropriate behaviors and thoughts, regulate our attention, monitor our actions, and plan and organize for the future. Neuropsychological and imaging studies indicate that these prefrontal cortex functions are weaker in patients with attention-deficit/hyperactivity disorder and contribute substantially to attention-deficit/hyperactivity disorder symptomology. Research in animals indicates that the prefrontal cortex is very sensitive to its neurochemical environment and that small changes in catecholamine modulation of prefrontal cortex cells can have profound effects on the ability of the prefrontal cortex to guide behavior. Optimal levels of norepinephrine acting at postsynaptic α-2A-adrenoceptors and dopamine acting at D1 receptors are essential to prefrontal cortex function. Blockade of norepinephrine α-2-adrenoceptors in prefrontal cortex markedly impairs prefrontal cortex function and mimics most of the symptoms of attention-deficit/hyperactivity disorder, including impulsivity and locomotor hyperactivity. Conversely, stimulation of α-2-adrenoceptors in prefrontal cortex strengthens prefrontal cortex regulation of behavior and reduces distractibility. Most effective treatments for attention-deficit/hyperactivity disorder facilitate catecholamine transmission and likely have their therapeutic actions by optimizing catecholamine actions in prefrontal cortex.

My simplistic understanding is that when there is hypofrontality, psychostimulants will improve the signal:noise ratio in the prefrontal cortex, thereby addressing the dysregulation in executive function seen in ADHD.

Cynical answer the question

ADHD is the label given to someone who is impulsive, unmotivated and bad at school and whose symptoms improve when they're given psychostimulants. This isn't a statement about whether or not ADHD does or doesn't exist, it's a statement about how its currently diagnosed and treated, hence my use of the term hypofrontality-mediated unfulfilled potential.

References

Antshel, K. M., Faraone, S. V., Stallone, K., Nave, A., Kaufmann, F. A., Doyle, A., ... & Biederman, J. (2007). Is attention deficit hyperactivity disorder a valid diagnosis in the presence of high IQ? Results from the MGH Longitudinal Family Studies of ADHD. Journal of Child Psychology and Psychiatry, 48(7), 687-694.
DOI: 10.1111/j.1469-7610.2007.01735.x

Arnsten, A. F., & Li, B. M. (2005). Neurobiology of executive functions: catecholamine influences on prefrontal cortical functions. Biological psychiatry, 57(11), 1377-1384.
DOI: 10.1016/j.biopsych.2004.08.019

Fisher, B. C., & Beckley, R. A. (1998). Attention deficit disorder: Practical coping methods. Boca Raton, FL: CRC Press.