Neurobiology of Addiction

Question 1

Outline the criteria for dependance as stated in ICD-10.

Answer 1

• A strong desire to take the substance
• Difficulties in controlling substance use
• A physiological withdrawal state
• Tolerance
• Neglect of alternative pleasures
• Persistence despite evidence of harm

Question 2

CAGE

Answer 2

Cut-down.
Annoyed.
Guilty.
Eye-opener.

Question 3

What is CAGE used for?

Answer 3

As a screening test to help identify potential problems with addiction/dependence

Question 4

What is meant by ‘incentive salience’?

Answer 4

Attributing ‘want’

Question 5

What parts of the brain does the reward pathway involve?

Answer 5

1. Ventral tegmental area (VTA)
2. Nucleus accumbens
3. Prefrontal cortex

Question 6

What kind of signalling is DA activity in the mesolimbic pathway?

Answer 6

A motivating signal

Question 7

What does DA signalling in the mesolimbic pathway do?

Answer 7

Incentivises behaviour.

Question 8

What type of experience is DA signalling in the mesolimbic pathway involved in?

Answer 8

Normal pleasurable experiences

Question 9

What do natural rewards elevate?

Answer 9

Dopamine levels

Question 10

How is the pleasure pathway blocked?

Answer 10

By cutting the pathways or by administering dopamine antagonists

Question 11

As a person becomes addicted to something, they can tolerate ______ levels, D2 receptors ________ and it takes ____ for them to be stimulated

Answer 11

HIGHER
DECREASE
MORE

Question 12

Non- addicted controls had increased blood flow to the striatum upon winning

Answer 12

TRUE

Question 13

What receptors are decreased by addiction?

Answer 13

Dopamine D2 receptors

Question 14

What does tolerance to reward occur due to?

Answer 14

Repeated dopamine release, meaning that dopamine receptors down regulate

Question 15

What is increased during abstinence from an additive substance?

Answer 15

Threshold for rewards

Normal experiences don’t evoke adequate reward response

Question 16

Even with PROLONGED ABSTINENCE from substance abuse, there is still an increased threshold for rewards

Answer 16

TRUE

Question 17

In relation to drug-taking, what is positive reinforcement?

Answer 17

Occurs in the initial stages of drug taking which are driven by reward.

Question 18

In relation to drug taking, what is negative reinforcement?

Answer 18

How, eventually, drug taking becomes a thirst.

Question 19

What does the pre-frontal cortex help to do?

Answer 19

Helps intention guide behaviour

Question 20

What does the prefrontal cortex modulate?

Answer 20

The powerful effects of the reward pathway

Question 21

What other roles does the prefrontal cortex play?

Answer 21

• Sets goals and focuses attention
• Makes sound decisions
• Keeps emotions and impulses under control to achieve long term goals

Question 22

Explain how cortical maturation occurs.

Answer 22

Progresses in a back-to-front direction, beginning in the primary motor cortex and spreading anteriorly over the superior and inferior frontal gyri, with the prefrontal cortex developing last.

Question 23

What direction does cortical maturation occur in?

Answer 23

Back to front

Question 24

Compared to limbic (emotional) systems, when do frontal lobe areas that mediate executive functioning mature?

Answer 24

Later

Question 25

What does dopamine release affect?

Answer 25

* Ability to update information within the PFC. * Ability to select new goals. * Ability to avoid compulsive repetition of a behaviour.

Question 26

What is the affect of addictive drugs on the prefrontal cortex?

Answer 26

They provide a potent signal that disrupts normal dopamine-related learning in the PFC.

Question 27

What is the relationship between age at which drug experimentation starts, and duration of relationship with drugs?

Answer 27

The earlier the age at which drug experimentation starts, the longer the relationship with drugs.

Question 28

What are the hippocampus, striatum and amygdala critical in?

Answer 28

Acquisition, consolidation and expression of drug stimulus learning

Question 29

What type of learning is the i) striatum ii) hippocampus responsible for?

Answer 29

i) Habit learning. | ii) Declarative learning.

Question 30

What does the orbit-frontal cortex do?

Answer 30

Provides internal representations of the saliency of events, and assigns value to them

Question 31

What is the KEY function of the orbit-frontal cortex?

Answer 31

MOTIVATION TO ACT

Question 32

What happens to the orbit-frontal cortex when drug addicts are presented with cues?

Answer 32

There is increased activation of this area

Question 33

What does hyperactivity of the orbit-frontal cortex correlate with?

Answer 33

Self-reported drug cravings, following exposure to cues

Question 34

Overall changes in the OFC still stay even with abstinence

Answer 34

TRUE

Question 35

Does addiction have a genetic component?

Answer 35

YES

Question 36

How much of the risk of addiction is due to genetics?

Answer 36

40-60%

Question 37

In relation to drugs, what may genetics affect?

Answer 37

* The way we respond to drugs metabolically * Behavioural traits that predispose us to take drugs * How rewarding we find drug taking

Question 38

What impact do DRD2 receptor levels have on risk of addiction?

Answer 38

Low DRD2 receptors result in high risk

Question 39

In relation to dopamine, what does acute stress trigger?

Answer 39

Release of dopamine in the neural reward pathway

Question 40

In dependent individuals, what can a rapid increase in release of dopamine do?

Answer 40

Motivate drug seeking in dependant individuals

Question 41

What is the effect of chronic stress on dopaminergic activity? What are the results of this?

Answer 41

Chronic stress leads to dampening of dopaminergic activity through down-regulation of D receptors * this reduces sensitivity to normal rewards * encourages exposure to highly rewarding behaviours

Question 42

Overstimulation of the reward pathway leads to ____________

Answer 42

DESENSITISATION

Question 43

* Pre frontal cortex dysfunctional in addicted people * Pre frontal cortex puts the brakes on the reward pathway * Pre frontal cortex matures late and is vulnerable whilst developing

Answer 43

TRUE TRUE TRUE