3. Inattention
• Distractible
• Difficulty maintaining attention / concentrating
• Not listening when spoken to
• Difficulty organising / following instructions
• Avoiding activities involving mental effort
• Forgetful
4. Hyperactivity symptoms
• Fidgety
• Getting up from seat when should be seated
• Running about when should be still
• Noisy doing leisure activities
• Often ‘on the go’ or acts as if ‘driven by a motor’
• Talking excessively
5. Impulsivity
• Interrupting or intruding on others
• Blurting out answers to questions
• Trouble waiting in turn
• Risk taking
• Spending
• Fighting
6. Prevalence of ADHD
• 40% of children exhibit parent-reported problems with
attention or hyperactivity corresponding to ADHD
diagnostic criteria at age 4.1
• 5.29%2 and 7.1%3 in children and adolescents.2,3
• 3.4% (range 1.2–7.3%) in adults.4
1. Jacobsen et al (2018), 2.Polanczyk G (2007), 3. Willcutt (2012), 4. Fayyad (2007)
7. Aetiology of ADHD
Genetic
• Parents & siblings of ADHD children are 4 to 5 times
more likely to have ADHD than general population.
• Twin studies give a heritability estimate of 70 - 90%.
• Over 50 different genes implicated in ADHD
8. Aetiology of ADHD
Others
• Neonatal hypoxia
• Lead exposure
• Extreme prematurity & low birth weight
• Intrauterine exposure to alcohol (FAS) and nicotine
• Acquired brain disorder (encephalitis or trauma)
• Diet
9. Prevalence of ADHD
• 40% of children exhibit parent-reported problems with
attention or hyperactivity corresponding to ADHD
diagnostic criteria at age 4.1
• 5.29%2 and 7.1%3 in children and adolescents.2,3
• 3.4% (range 1.2–7.3%) in adults.4
1. Jacobsen et al (2018), 2.Polanczyk G (2007), 3. Willcutt (2012), 4. Fayyad (2007)
10. Brain Plasticity
• Brain plasticity (neuroplasticity) refers to the extraordinary
ability of the brain to modify its own structure and function
following changes within the body or in the external
environment.
11. Brain structures
• Working memory
• Decision making
• Insight
• Judgement
• Inhibition of
distractions
Thinner in ADHD
Prefrontal Cortex
27. Genetics of ADHD
Polymorphisms which may influence susceptibility to
ADHD:
• D4
• D5
• DAT
• Dopamine β Hydroxylase
• SNAP 25
• Serotonin transporter
• HTR 1B
28. How does Methylphenidate work?
Dopamine Transporter
Presynaptic vesicle
Post synaptic receptor
Dopamine
29. How does Dexamfetamine work?
Dopamine Transporter
Presynaptic vesicle
Post synaptic receptor
Dopamine
30. How does Atomoxetine work?
Noradrenaline Transporter
Presynaptic vesicle
Post synaptic receptor
NA & Dopamine
31. How does Guanfacine work?
Noradrenaline Transporter
Presynaptic vesicle
Post synaptic receptor
NA & Dopamine
Guanfacine
32. Summary
ADHD is associated with differences in:
• Brain structure
• Brain function
• Brain chemistry
• Brain maturation
ADHD is a continuum of symptoms of inattention,
impulsivity and restlessness
The brain is plastic
Hinweis der Redaktion
Executive control circuit: role in making decisions and learning new tasks. May be responsible for mind wandering and lack of motivation or impulse control.
Default mode network: switches off default network activity when focus is needed.