Lecture 1: Drug Craving & Neural Biases Flashcards
Describe the 11 features of substance use disorder
- Alcohol is often taken in larger amounts or over a longer period than was intended.
- There is a persistent desire or unsuccessful efforts to cut down or control alcohol use.
- A great deal of time is spent in activities necessary to obtain alcohol, use alcohol, or recover from its effects.
- Craving, or a strong desire or urge to use alcohol.
- Recurrent alcohol use resulting in a failure to fulfill major role obligations at work, school, or home.
- Continued alcohol use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of alcohol.
- Important social, occupational, or recreational activities are given up or reduced because of alcohol use.
- Recurrent alcohol use in situations in which it is physically hazardous.
- Alcohol use is continued despite knowledge of having a persistent or recurrent physical or psychological problem that is likely to have been caused or exacerbated by alcohol.
- Tolerance, as defined by either of the following:
a. A need for markedly increased amounts of alcohol to achieve intoxication or desired effect.
b. A markedly diminished effect with continued use of the same amount of alcohol. - Withdrawal, as manifested by either of the following:
a. The characteristic withdrawal syndrome for alcohol
b. Alcohol is taken to relieve or avoid withdrawal symptoms.
How many people in the Netherlands suffer from substance abuse at some point in their lives
17%
What are 9 risk factors for substance abuse
- early aggressive behavior in childhood
- early drug use
- lack of parental supervision
- substance abuse by caregivers
- low refusal skills
- poor social skills
- drug availability
- community poverty
- administration through smoking or injection —> differs between drugs
What are 6 protective factors of substance abuse
- self-efficacy (belief in self control)
- academic performance
- parental monitoring and support
- positive relationships
- school anti-drug policies
- neighborhood resources
Explain the brain disease model of addiction
= addiction is a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences
What are 3 critics of the brain disease model
- Addictive behavior is voluntary and self-destructive because ultimately people can stop out of choice (which is different from diseases such as cancer)
- Addicts are not blameless victims of some terrible illness they have no control over —> takes away the responsibility of the person
- Most people beat addiction by working really hard at it; if only we could say the same about medical diseases
What area in the brain is most related to (natural) rewards and what happens in this area with natural rewards compared to drugs
The nucleus accumbens (NA)
Natural rewards lead to increased release of dopamine levels; drugs do this too but much more so than natural reinforcers
Explain structural differences in DA system and give two explanations for it
PET studies show lower density of dopamine (DA) D2 receptors in addicted individuals, relative to controls
1. Homeostatic account = increased dopamine activity due to drugs leads to a decrease of dopamine D2 receptors
2. Reward deficiency syndrome theory = direct relatives of drug addicts also show relatively low D2 density —> number of D2 receptors related to individual differences in reward sensitivity; less receptors = lower reward sensitivity and higher vulnerability for addiction
Explain how Pavlovian learning relates to substance abuse
In addicts, images of drugs/alcohol can activate the NA relative to neutral images —> this is because people learn to associate these cues with the actual thing
Explain how prediction error relates to substance abuse
When the prediction of reward in a situation is not yet completely accurate, this leads to surprise and a reward prediction error occurs. Midbrain dopamine neurons encode this prediction error which is a signal to cortico-striatal brain circuits that the current reward value does not match the expected value —> it functions as a teaching signal. Once the CS-US relationship has been learned, the predictive cue (CS) will evoke a dopamine response. Therefore, the DA neurons fire at the (unexpected) presentation of the CS (instead of the fully predicted US).
Explain the Incentive-Sensitization theory
Repeated substance abuse leads to a decrease in liking (the hedonic experience), but at the same time, “wanting” of the substance increases.
Repeated drug use leads to changes in the mesolimbic dopamine system which becomes sensitized (hyperreactive) to incentive effects of drugs and drug-associated cues
Define “wanting”
= an extreme craving that does not have to be experienced consciously, and that is triggered especially by drug-associated cues
In what 4 ways is the incentive salience of drug-associated stimuli expressed behaviorally
- Drug-associated stimuli elicit attention and approach towards them, acting as motivational agents; CSs become motivational agents
- Drug-associated stimuli (CSs) become reinforces in their own right
- Drug-associated stimuli (CSs) and drugs can induce relapse (reinstatement)
- Willingness/motivation to work for the drug increases
What are 4 research paradigms that look into incentive sensitization and what is tested with it
- Conditioned place preference paradigm; how much time does a rat (or human) spend in a certain chamber when they are (not) associated with a drug —> rats spend more time in chamber associated with alcohol than ones that is not (CSs become motivational agents
- Conditioned reinforcement paradigm; in phase 1, a light (CS) is shown to lead to a drug (US); in phase 2, response 1 is shown to lead to a light and response 2 is shown to lead to nothing —> rats will perform R1 more vigorously than R2 (CSs become reinforcers in their own right)
- Drugs reinstate drug seeking/Reinstatement paradigm; reinstatement of the drug can happen because of different stimuli —> conditioned reinstatement (= drug-associated cues), drug reinstatement (= having one drink can lead to full relapse), stress reinstatement (= stressful episodes can lead to reinstatement) —> CSs can lead to relapse
- Progressive ratio experiments; instrumental response to obtain a substance gradually increases —> rats will work harder to self-administer a drug when they have been pre-exposed to this drug (willingness to work for drug increases)
Break point
= point at which human/animal is no longer willing to work harder to obtain the drug
