Berridge & Robinson - Addiction as Incentive Sensitization

Question 1

What does the incentive-sensitization theory aim to explain?

Answer 1

• Why addicts relapse even when they no longer find the drugs pleasurable
• Why drug-taking becomes compulsive and hard to control

Question 2

On which distinct brain processes do liking & wanting depend?

Berridge & Robinson = B&R

Answer 2

• Liking = generated by hedonic hotspots in brain regions like the nucleus accumbens and ventral pallidum
• Wanting = dopamine-related pathways (i.e., mesolimbic system)

Question 3

To what process in the incentive-sensitization theory is dopamine (moreso) linked?

Answer 3

“Wanting” (i.e., craving)

Question 4

What happens with repeated drug use to the mesolimbic system?

B&R

Answer 4

Causes sensitization of mesolimbic dopamine system
- Above causes intense “wanting” for drugs, triggered by cues or contexts

Question 5

What evidence is there for the incentive-sensitization theory?

B&R

Answer 5

Behavioural experiments in animals:
- Rats show increased motivation (more work or risk-taking) for drugs over time, even without increased pleasure
- Matches self-reported human experience

Human brain imaging:
- Drug cues trigger strong activation in reward-related brain areas (even in absent users)

Question 6

What is an implication for relapse of the Incentive-Sensitization theory?

B&R

Answer 6

Sensitized incentive systems remain dormant but can be reactivated by stress, drugs, or drug-associated cues (explaining relapse after long abstinence)

Question 7

What is a problem with sensitization?

Answer 7

It is long-lasting and difficult to reverse

Question 8

What is cue exposure therapy (in the context of addiction)?

Answer 8

Repeated exposure to drug-related cues, without the drug being given (aims to extinguish the conditioned response)

Question 9

Why does cue exposure therapy often fail?

Answer 9

• If a cue has become hypersalient by repeated drug use, it continues to trigger intense motivation (wanting)
• These brain-level changes are deep and persistent- thus incentive salience is not easily unlearned
• Learning is context specific (renewal in real-world settings), and things like reinstatement & spontaneous recovery are possible

Question 10

When does the incentive-sensitization theory postulate addiction arises?

B&R

Answer 10

When neuroadaptations increase incentive salience of drug-related stimuli

Question 11

What is the difference between incentive & sensitization (B&R context)?

Answer 11

• Sensitization is what happens to the mesolimbic system with repeated drug use (i.e., make the system more sensitive to drug cues)
• The latter leads to the drugs itself becoming hyper-salient, i.e., the drug has high incentive salience (highly wanted/sought out)

Question 12

What is an important factor in whether or not sensitization happens?

B&R

Answer 12

Vulnerability; it is not a universal outcome