ADHD

Question 0

What is the age cutoff before which symptoms must have started for ADHD to be diagnosed?

Answer 0

Symptoms must have onset before age 7 to be classified as ADHD.

Question 1

3 main axes of ADHD?

Answer 1

Inattention
Hyperactivity
Impulsivity

Question 2

If a kid has trouble paying attention at school, but no such problems at home, could this be ADHD?

Answer 2

No. To be classified as ADHD, problems must occur both at home and at school (or work).

Question 3

Approximate prevalence of ADHD in kids age 8-15?

Approximate prevalence of ADHD in adults aged 18-44?

Answer 3

Age 8-15: roughly 8.7%

Age 18-44: roughly 4.4%

Question 4

What is the “heritability” of ADHD?

Answer 4

0.75 - just know that it’s quite high.

Question 5

What are most of the genes associated with ADHD related to?

Answer 5

Mostly dopamine signaling.

Also some serotonin signaling.

Question 6

Name 2 specific genes associated with ADHD. What do they do?

Answer 6

DRD4 - dopamine receptor

DAT - dopamine transporter

Question 7

What environmental factor has known to be strongly correlated with ADHD when ADHD-associated variants of DRD4 and DAT are present?

Answer 7

Smoke exposure in utero. (but remember that correlation =/= causation!!)

Question 8

What’s the posterior system of attention: Purpose? Regions of brain used? Neurotransmitter used?

Answer 8

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).

Question 9

What’s the anterior system of attention: Purpose? Regions of brain used? Neurotransmitter used?

Answer 9

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.

Question 10

Is ADHD all about “attention”?

Answer 10

No. There’s also a deficit in “intention,” i.e. executive function.

Question 11

What 2 deficits in ADHD are usually most relevant for young adults?

Answer 11

Deficits in working memory and verbal learning.

Question 12

What’s the test for ADHD?

Answer 12

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.)

Question 13

Which three areas of the brain are grossly altered in ADHD? How are they altered? Other area with decreased activity?

Answer 13

Orbital-Prefrontal Cortex, Basal Ganglia, and Cerebellum are smaller, less active, and less developed.
Anterior cingulate also has less activity.

Question 14

Can reduced activity of the anterior cingulate gyrus in ADHD be corrected?

Answer 14

Yes. Methylphenidate increases activity in this area.

Question 15

What can you see in the nucleus accumbens in PET scans of kids with ADHD?

Answer 15

Decreased levels of dopamine transporters (DAT).

Question 16

What’s one specific area of the brain affected by catecholamines relevant to ADHD?

Answer 16

Pre-frontal cortex. Too much or too little catecholamine signaling impairs function.

Question 17

First-line therapy for ADHD?

Answer 17

CBT + stimulant. (data shows this to be much more effective than CBT alone)

Question 18

3 first-line drugs used for ADHD?

Answer 18

Stimulants
Atomoxetine (NE reuptake inhibitor)
Alpha-adrenergic agonists

Question 19

How do the effects of methylphenidate and amphetamine vary?

Answer 19

Amphetamine allows dopamine escape from vesicle -> increased dopamine in synapse.
Methylphenidate blocks dopamine reuptake.