ADHD 1

Question 1

characteristics of ADHD

Answer 1

• hyperactivity, impulsivity and attentional problems
• often has difficulty sustaining attention in tasks or play activities
• often fidgets with or taps hands or feet or squirms in seat
• several symptoms have to be present before age 12 and manifest in more than one context

Question 2

ADHD in DSM 5

Answer 2

• ‘A persistent pattern of inattention and/or hyperactivity-impulsivity that interferes with functioning or development’
• recognises three ‘presentations’:
  1. predominantly inattentive
  2. predominantly hyperactive-impulsive
  3. combined

Question 2

ICD 11 and ADHD

Answer 2

‘a persistent pattern of inattention and/or hyperactivity-impulsivity that has a direct negative impact on …. functioning’

Question 3

ADHD prevalence

Answer 3

• UK = ~5% of children/adolescents have a diagnosis of ADHD
• boy: to girl ratio = ~3:1
• symptoms continue into adulthood in 8-43% of cases (gender gap may narrow)
  –> activity issues decline and attentional issues remain

Question 4

baseline treatment for ADHD

Answer 4

• in kids over 5, adolescents and adults
• DL-amphetamine
  or
• methylphenidate
• class B drugs
• drugs of abuse
• effective but addictive

Question 5

estimated cost of ADHD in the UK

Answer 5

• combined cost of children and adolescents is roughly £2.4 billion
• drugs and treatments
• cost of juvenile detention

Question 6

ADHD in 1902

Answer 6

• George Fredric Still (paediatrician)
• gave a series of lectures
• talked about a group of kids he has been studying
• described 20 cases of children with a “defect of moral control…. (don’t think about others) without general impairment of intellect and without physical disease”
• “the immediate gratification of self without regard either to the good of others or to the larger and more remote good of self”
  -“fidgety….”
• “a quite abnormal incapacity for sustained attention”

Question 7

ADHD 1917-1928

Answer 7

• Encephalitis lethargica epidemic
• less severe had cold symptoms, more severe were more rigid and statue like (eyes became almost paralyzed)
• many affected children who survived the encephalitis, subsequently showed abnormal behaviour
• “Postencephalitic behaviour disorder”
• children often became hyperactive, distractible, irritable, antisocial, destructive, unruly, and unmanageable in school
• first association of (now) ADHD with brain damage
• when adults recovered they often had Parkinson’s symptoms

Question 8

ADHD 1940s/50s Minimal brain damage

Answer 8

• assumption that minimal damage to the brain, even when it cannot be demonstrated objectively, causes postencephalitic-type behaviour disorder
• brain damage would be inferred just from looking at kid’s behaviour
  –> not great

Question 9

ADHD 1960s

Answer 9

• Minimal brain dysfunction (MBD)
• became clear that this disorder (“hyperkinetic impulse disorder”) could occur in the absence of explicit brain damage
• the Oxford International Study Group of Child Neurology therefore advocated a shift in terminology by replacing the term “minimal brain damage” by “minimal brain dysfunction”
• certain behaviours are not always linked to brain damage

Question 10

ADHD 1968

Answer 10

• minimal brain dysfunction was eventually considered too broad
• leading to a focus on more specific symptoms… (especially hyperactivity)
• 1968 DSM II:
  –> “Hyperkinetic Reaction of Childhood”

Question 11

ADHD in the 1970s

Answer 11

• throughout 70s, developing realisation that attentional problems were as significant, or more significant, than hyperactivity in this patient group
• inattention now seen as important

Question 12

ADHD 1980

Answer 12

• 1980 DSM III:
  –> “Attention Deficit Disorder (ADD)”
  –> with or without hyper-activity
• hyperactivity was no longer an essential diagnostic criterion for the disorder
  –> could just have issues with attention/inattention
• developed three separate symptom lists for:
  1. inattention
  2. impulsivity
  3. hyperactivity

Question 13

ADHD 1987

Answer 13

• DSM III-R:
  –> “Attention Deficit Hyperactivity Disorder”
• brought the symptom list together
• now could have attention issues, or hyperactivity issues OR BOTH

Question 14

ADHD 1994, 2000, 2013

Answer 14

• DSM IV 1994
  –> first time ADHD was able to be seen in adults and children
• DSM IV-TR 2000
  –> ADHD in adults and kids
• DSM 5 2013
  –> ADHD in adults and kids

Question 15

impact of ADHD

Answer 15

• DSM 5:
  –> there is clear evidence that the symptoms interfere with, or reduce the quality of, social, academic, or occupational functioning
• ADHD associated with:
  –> poorer educational attainment

Question 16

impact of ADHD - Fleming et al. (2017) - education

Answer 16

• poor educational attainment
• 4 Scotland-wide NHS databases
• 4 Scotland-wide school databases
• school leavers 2009-13
• ADHD vs non-ADHD
• Likelihood (OR)
  Sub-GCSE qualifications
• poorer results in ADHD kids
  –> slightly worse for boys than girls

Question 17

impact of ADHD - Klein et al. (2012) - employment

Answer 17

• poor occupational attainment
• adults (mean age 41) diagnosed with ADHD at 6 -12 years of age
• vs controls
• less employed with ADHD (84% vs 95%)
• lower salaries in ADHD
  (60k vs 100k)

Question 18

impacts of ADHD - Hoza et al. (2005) - child classmate evaluations

Answer 18

• children with ADHD
  –> 7.0-9.9 years
• and their same sex classmates
• study where kids are asked about who they like the most/least
• less popular with ADHD
• more rejected with ADHD
• ADHD and control are equal for average rating

Question 19

impact of ADHD - Lange et al (2016) - physical health

Answer 19

• physical health problems
• accidents over the last 12 months requiring medical treatment in children with ADHD (10.4 years old) and controls were recorded
  –> ADHD = 23%
  –> control = 15.35
• higher in ADHD kids

Question 20

impact of ADHD - Larson et al (2010) - mental health

Answer 20

• mental health problems
• kids ages 6-17
• much higher anxiety and depression in ADHD kids compared to non ADHD kids
• also higher autism and tourette likelihood in ADHD kids

Question 21

impact of ADHD - Levy et al., (2014) - drugs

Answer 21

• drug addiction
• higher drug dependence in adults for those with ADHD compared to non-ADHD

Question 22

negative effects of ADHD on:

Answer 22

• academic achievement
• occupational achievement
• social integration
• physical health
• mental health

Question 23

summary of ADHD (consequence and symptoms)

Answer 23

• ADHD is characterised by hyperactivity, impulsivity and attentional problems
• it affects around ~5% of children/adolescents, and symptoms can continue into adulthood in up to one half of cases
• clinical awareness of the condition dates back to the early years of the 20th century
• term ‘ADHD’ first appeared in the DSM III-R (1987)

Question 24

2 classical theories of ADHD

Answer 24

1. something to do with frontal cortex
2. something to do with dopamine

Question 25

classical theory 1 of ADHD - frontal cortex

Answer 25

• has something to do with the frontal cortex
• 3 types of evidence:
  1. neuropsychology
  2. structural imaging
  3. functional imaging

Question 26

neuropsychology evidence for frontal cortex damage and ADHD

Answer 26

• the symptoms of ADHD are similar to the changes following frontal cortex damage
• impulsivity measured using the ‘Iowa Gambling Task’

Question 27

Iowa Gambling Task

Answer 27

• different deck of cards
• some are advantageous
• some are disadvantageous
• in disadvantageous you gain more now but also lose more later on
  –> net of 250 loss
  –> short term gain
• in advantageous you gain less now more also lose less later
  –> net gain of 250
  –> less reward immediately but greater later reward

Question 28

results of Iowa gambling task

Answer 28

• ADHD pick disadvantageous over advantageous
  –> want short term reward
  –> more impulsive choice
• similar to those with brain damage to frontal cortex who are more impulsive

Question 29

delay aversion (reward)

Answer 29

• people with ADHD want immediate reward
• take it whilst its on offer

Question 30

Barkley’s ‘behavioural disinhibition’ theory of ADHD (executive)

Answer 30

• Professor of Psychiatry at the Medical University of South Carolina
• sees poor behavioural inhibition as the central deficiency in ADHD
• accounts for attentional and kinetic symptoms
• lack of ‘Self-control’

Question 31

Phineas Gage

Answer 31

• serious damage to his frontal cortex
• showed disinhibited behaviour
• similar to ADHD

Question 32

structural evidence for ADHD and frontal cortex damage

Answer 32

• frontal lobe grey matter volume is lower in those with ADHD
• 232.87 vs 260.07

Question 33

functional PET evidence for frontal cortex damage and ADHD

Answer 33

• a study that used PET scanning
• radioactive version of flourine used to emit positrons
• deoxy glucose injected into brain
• when brain is active it needs large supply for glucose
• radioactive area associated with glucose
  –> those were the active areas
• got kids to do a basic and boring task
  –> less brain activity in ADHD kids in this task than non ADHD kids
  –> frontal areas perform less well #
• structural and functional issues in ADHD brains

Question 34

classical theory 2 in ADHD - dopamine

Answer 34

• it has something to do with dopamine
• 3 types of evidence:
  1. medication
  2. imaging
  3. reward/reinforcement

Question 35

medication evidence for dopamine in ADHD

Answer 35

• drugs used to treat ADHD increase dopamine levels
• Microdialysis:
  –> a small, semi-permeable probe is inserted into a specific brain site
  –> fluid is perfused through the probe and chemicals in the extracellular fluid diffuse across the membrane and are collected
  –> samples are then analyzed using chromatography methods (e.g. HPLC)
• dopamine levels in the striatum after i.p. D-Amphetamine or methylphenidate increase

Question 36

imaging evidence for dopamine in ADHD

Answer 36

• ADHD is associated with an increase in dopamine reuptake
• can use SPECT scans
  –> single photon emission tomography
  –> more reuptake proteins for dopamine in ADHD individuals

Question 37

reward/reinforcement evidence for dopamine in ADHD

Answer 37

• ADHD is associated with changes in response to ‘reward’
  –> increases in dopamine in response to food
  –> increase in response to sex

Question 38

Disruption of learning by non-contingent reinforcement (Douglas and Parry, 1983)

Answer 38

• elementary school children (mean age around 9.5 years old)
• 33 with ADHD, 33 without
• had to release a response key when a stimulus light came on (reaction time task)
• 3 conditions:
  1. rewarded on every trial when they got faster
  2. rewarded on every other trial when they got faster
  3. rewarded randomly (non-contingent)
• reward = told they were “very good”, “excellent” or “very fast”
• non-contingent reinforcement schedule resulted in slower mean reaction times in the ADHD sample
  –> harder to figure out reward schedule
• also delay aversion

Question 39

classical theories suggest (summary)

Answer 39

• that the disorder has something to do with the frontal cortex
• that the disorder has something to do with dopamine
• in the case of the frontal cortex evidence comes from:
  –> neuropsychology
  –> structural imaging
  –> functional imaging
• in the case of dopamine, evidence comes from:
  –> medication
  –> imaging (SPECT)
  –> reward/reinforcement