Attention Deficit Hyperactivity Disorder Flashcards
Define ADHD and its criteria Outline the concept of co-morbidity List the co-morbid conditions in ADHD Outline genetic and psychosocial aetiological factors Relate the neuropsychology of ADHD to its neurobiology Describe the management options and how they might work
Define ADHD
The triad of inattention, hyperactivity, and impulsivity, present for over 6 months before the age of 7 and causing significant distress or social impairment
State the criteria for inattention
At least 6 of: failure to sustain attention, failure to complete instructions or work, failure to listen, losing things, careless errors, easy distractibility, avoidance of tasks requiring mental error, forgetfulness and poor planning
State the criteria for hyperactivity
At least 3 of: fidgeting or squirming, undue noisiness, leaving seat in class, excess running about, excess motor activity
State the criteria for impulsivity
At least 1 of: blurting out answers to questions, excess talking, failure to wait one’s turn, poor self-control, interrupting or intruding on others, risk-taking
What percentage of patients with ADHD have comorbid conduct disorder?
25-50%
What percentage of patients with ADHD have comorbid anxiety disorder?
25%
What percentage of patients with ADHD have comorbid learning difficulties?
30%
State a difficulty comorbidities pose in diagnosing ADHD
The symptoms often overlap - for example, inattention is a feature of ADHD, depression, anxiety, and autism spectrum disorder
State the difference in ADHD prevalence between the UK and US
US: 8.8% diagnosed, 6.1% on medication
UK: 1.7% diagnosed, 0.8% on medication
State the ratio of ADHD in males to females
3:1
Is there evidence that ADHD incidence is increasing?
No - but the number of individuals presenting to clinic and taking medication has
State 3 population groups with higher prevalence of ADHD
Inner cities, lower socio-economic classes, prisons
How much more at risk of developing ADHD is the child of a parent with ADHD than the child of a parent without ADHD?
8x
What is the ADHD concordance rate between monozygotic twins?
80%
State the approximate heritability of ADHD
75%
Give at least 2 candidate genes for involvement in ADHD
Tyrosine hydroxylase (involved in DOPA synthesis), dopamine receptors D2, D3, and D5, catecholamine methyl transferase (COMT), nicotinic receptors, SNAP-25 (involved in axonal growth)
State a potential prenatal risk factor for ADHD
Maternal smoking, maternal alcohol or substance misuse, maternal stress
State a perinatal risk factor for ADHD
Very low birthweight
State a potential postnatal risk factor for ADHD
Environmental lead, zinc deficiency, magnesium deficiency, organophosphates
State at least 3 psychosocial environmental risk factors for ADHD
High numbers of critical comments, poor encouragement, inconsistent parenting, low sensitivity to child’s needs, maltreatment or physical discipline, maternal depression
Give 3 examples of executive functions
Planning, flexible strategy, impulse control, orientation to salient stimuli, suppression of inappropriate actions
Name 2 tests of impulse control
Wisconsin card sorting test, Stroop test
Describe the Stroop test
The words of colours flash up in different colours and the individual has to say the colour instead of the word (e.g. if orange was written in green, say green)
Name a gene variant associated with decreased executive function
COMT gene variant val/val159met
Describe the differences in the prefrontal cortex of an individual with ADHD on MRI
Decreased brain size (but also seen in non-ADHD siblings) and delay of brain development by 2-3 years
Describe the differences in the prefrontal cortex of an individual with ADHD on SPECT MRI
Decreased blood flow (but also seen in non-ADHD siblings)
Describe the differences in the prefrontal cortex of an individual with ADHD on fMRI
Increased dopaminergic transporter density, so dopamine is cleared more rapidly from the synapse
Describe the differences in the prefrontal cortex of an individual with ADHD on diffusion tensor imaging
Decreased white matter (but also in non-ADHD parents), with connectivity relative to cognitive performance
Describe the basal ganglia and cerebellum of ADHD patients on MRI
Reduced in volume, with decreased blood flow to these areas
Name a risk gene for ADHD which influences basal ganglia volume
A 7-repeat allele for dopamine transporter 1 (DAT1)
What is the first line treatment for behaviour management in ADHD?
Environmental modification - school support, adaptations, parenting programs
What do parenting programs for ADHD involve?
Teaching the importance of realistic expectations, praise and reward, clear rules and expectations, keeping calm, quality time, and ‘time out’
When is medication appropriate for treating ADHD? (NICE, 2018)
When there are ongoing problematic symptoms despite attempts at environmental modification
What are the first-line medications for ADHD?
Methylphenidate and dexamphetamine
What is the second-line medication for ADHD?
Atomoxetine, a noradrenaline reuptake inhibitor with some action on dopamine reuptake
How do stimulants treat ADHD?
They readdress pathological underactivity by increasing synaptic dopamine
State some side effects of stimulants used in ADHD
Decreased appetite, weight, and growth, sleep changes, mood changes, slight increases in heart rate and blood pressure
What are the baseline tests before prescribing a stimulant for ADHD?
Height, weight, pulse, blood pressure, cardiac examination
What is the prognosis for untreated ADHD?
90% of untreated cases in childhood go on to develop conduct disorder
How many individuals still meet the diagnostic criteria for ADHD in adulthood?
15-33%
