ADHD Flashcards
What is the age cutoff before which symptoms must have started for ADHD to be diagnosed?
Symptoms must have onset before age 7 to be classified as ADHD.
3 main axes of ADHD?
Inattention
Hyperactivity
Impulsivity
If a kid has trouble paying attention at school, but no such problems at home, could this be ADHD?
No. To be classified as ADHD, problems must occur both at home and at school (or work).
Approximate prevalence of ADHD in kids age 8-15?
Approximate prevalence of ADHD in adults aged 18-44?
Age 8-15: roughly 8.7%
Age 18-44: roughly 4.4%
What is the “heritability” of ADHD?
0.75 - just know that it’s quite high.
What are most of the genes associated with ADHD related to?
Mostly dopamine signaling.
Also some serotonin signaling.
Name 2 specific genes associated with ADHD. What do they do?
DRD4 - dopamine receptor
DAT - dopamine transporter
What environmental factor has known to be strongly correlated with ADHD when ADHD-associated variants of DRD4 and DAT are present?
Smoke exposure in utero. (but remember that correlation =/= causation!!)
What’s the posterior system of attention: Purpose? Regions of brain used? Neurotransmitter used?
Orients and engages to novel stimuli. “Wake up and smell the coffee.”
Sup. parietal cortex, sup. colliculus, and pulvinar. Receives input from locus coeruleus (LC).
Uses norepinephrine (NE).
What’s the anterior system of attention: Purpose? Regions of brain used? Neurotransmitter used?
Reduces responsivity of neurons to new input. “Fixate on the coffee mug and drink from it.”
Uses the prefrontal cortex (PFC) and ant. cingulate for executive function. Receives inputs from ventral tegmental area (VTA).
Its activity relies upon dopamine signaling.
Is ADHD all about “attention”?
No. There’s also a deficit in “intention,” i.e. executive function.
What 2 deficits in ADHD are usually most relevant for young adults?
Deficits in working memory and verbal learning.
What’s the test for ADHD?
Trick question. There is none, because it’s so heterogenous. Tests are done for deficits in specific things (vigilance, response inhibition, verbal learning, executive function, etc. etc. etc.)
Which three areas of the brain are grossly altered in ADHD? How are they altered? Other area with decreased activity?
Orbital-Prefrontal Cortex, Basal Ganglia, and Cerebellum are smaller, less active, and less developed.
Anterior cingulate also has less activity.
Can reduced activity of the anterior cingulate gyrus in ADHD be corrected?
Yes. Methylphenidate increases activity in this area.
What can you see in the nucleus accumbens in PET scans of kids with ADHD?
Decreased levels of dopamine transporters (DAT).
What’s one specific area of the brain affected by catecholamines relevant to ADHD?
Pre-frontal cortex. Too much or too little catecholamine signaling impairs function.
First-line therapy for ADHD?
CBT + stimulant. (data shows this to be much more effective than CBT alone)
3 first-line drugs used for ADHD?
Stimulants
Atomoxetine (NE reuptake inhibitor)
Alpha-adrenergic agonists
How do the effects of methylphenidate and amphetamine vary?
Amphetamine allows dopamine escape from vesicle -> increased dopamine in synapse.
Methylphenidate blocks dopamine reuptake.
