Test 2

Question 1

What is addiction?

Answer 1

• Maladaptive behavioural problem of drug use
• overwhelming involvement with the use of drug (compulsive)
• high tendency to relapse w withdrawal

Question 2

The Disease Model

Answer 2

• addiction is a sin, treated by priests or the legal system

Question 3

Susceptibility model

Answer 3

• the problem is with the individual not the drug
• some individuals are more prone to developing substance abuse due to genetic makeup for ex, ALDH in elders and when drink lose consciousness
• Em Jellick: alcoholism is changes in structure or function of the body due to drinking that can cause death
• no addiction “gene” its a combo of many and due to heritability

Question 4

The Exposure models

Answer 4

• The drug changes the brain and a single exposure can cause long term changes.

Question 5

Carl Hart

Answer 5

• Addiction is a societal definition, if you gave ppl jobs or education they’ll do drugs for fun

Question 6

negative reinforcement model: Physical Dependance Model

Answer 6

• drug is taken to get rid of pains and then after to avoid withdrawal effects
• eliminates a negative consequence
• conditioned withdrawal can be triggered by env because you’re always in that area taking the drug, or in abstinent subjects.

Question 7

problems w physical dependance model

Answer 7

• doesn’t address the reason for developing drug use to dependance
• addiction can develop without physical withdrawal
• addicts rarely mention withdrawal as a reason for relapse
• craving for cocaine is higher after taking the drug

Question 8

Negative reinforcement model: The self-medication hypothesis

Answer 8

• The drug is used to medicate an existing negative state, ie anxiety, stress
• Tested by Wit et al. recruited volunteers first 4 days given a pill (blue vs red), days 5-9 given a choice and not much preference. Same for depression and amphetamine.
• preference dev for opiates if they know there’s pain

Question 9

Negative reinforcement model: The opponent process

Answer 9

• similar to homeostasis and the need for balance
• in the model: A kicks in faster as long as the stimulus is there, B is slower to start and its when the drug starts to metabolize. They are opponent models so when the effects of A are over, B decreases in affective state.
• After many exposures the brain is more efficient and therefore B is too (affective state), high is quick and small, then intense withdrawal.

Question 10

Negative reinforcement: allostatic model

Answer 10

• addiction is the result of the reward system being less efficient due to repeated exposure and anti reward systems
• ex: ICSS rats: inter cranial self stimulation, where rats self administered cocaine for 6 hours, and this caused an escalation of drug intake since it was a reliable reward. This causes the reward system to be diffident due to needing higher freq. Can find this out due to the M50s curve where if there’s a shift to the left it is rewarding and if you give something that blocks this reward it shifts to the right. The easiest way to compare is w M50S.

Question 11

Allostatic Model: Koob and Le Moal

Answer 11

• on top of everything else, anti-reward mechanisms (associated with stress, aversion, so they’re corticotropin releasing factors) are released in the brain. with the acute side it affects the CRF system HPA axis and could cause a relapse bc sensitized. vs repeated exposure where the same cycle happens over and over, the brain will adjust and won’t go back to baseline. So crashes, small high and lower allostatic baseline, take the drug to feel normal.

Question 12

Bozarth and Wise: Opiates can be rewarding independently from their withdrawal alleviating properties

Answer 12

• animals will readily admin to the VTA and not the PVG, because there is no reward in the PVG not because of withdrawal.
• morphine was self admin into the VTA and then after it was injected into dif areas so that the animals were dependent. After this they used naloxone in order to see withdrawal symptoms. Turns out they will only inject into VTA bc rewards

Question 13

What is a Positive Reinforcement model (jane stewart)

Answer 13

There is an incentive stimuli which triggers approach and consumption. Then there’s the central motivational state, this is when something needs to drive you to get the stim. Then the behavior occurs. System involved in reward directed behavior.

Question 14

positive reinforcement models: the hedonia model (DA –> pleasure model)

Answer 14

• the motivational system identified pleasure and drives a certain behavior to get more
• this is due to the mesolimbic DA system
• Roy Wise: sensory messages are translated into the hedonic message
  which tells us something is “yummy”
• drugs hijack this system and push it to high levels, anything activating DA is pleasurable

Question 15

The Hedonia model experiments

Answer 15

1. Psychostimulant drugs are self administered into the NAc, this increases the level of DA.
2. DA antagonists attenuated behaviors supported by almost all kinds of reward. This means if DA has such a role when blocked it should have an impact on behavior.
   ex: ICSS rats were trained to press a lever to get a reward in this case DA. When they were injected the response went down to 0 since there’s no more interest bc no reward. there was no motor impairment bc they still pressed the lever when the door was opened. There was an extinction
   ex2: rats were given food and received DA from it so they’d keep pressing the button. When they were given a DA antagonist, they learnt food was not as rewarding and due to this they started pressing the button less and less. W antagonist they have no expectation and then give a full resp when a reward is given bc frustrated.
   ex 3: Ratings of pleasure correlate with amount of DA receptors in the striatum. Subjects were given an infusion to ask for a rating on a scale. higher the high: binding potential was higher bc more DA released.

Question 16

problems with the hedonia hypothesis

Answer 16

1. some degree of reward function is possible even without DA (DA deficient mice). Nader and Van trained rats for conditioned place preference with morphine vs control w saline. Rats spent more time on morphine side, even when injected with an antagonist. Rats given morphine were then given heroin, They were then given 9 days to recover. Those rats had withdrawal and after they gave them a DA antagonist, they didn’t care abt side. (didn’t need da to know what side they wanna go on)
2. has been suggested for opiates there’s 2 reward systems: one for drug dependent subjects (DA dependent) and for non dependent ( DA independent). This is bc some receptors change their function when dependent on the drug so they’re DA dependent.
3. opiates act at 2 points, the VTA and the NAc. This means you can bypass the DA system due to rats injecting morphine at VTA and NS can bypass pleasure and get reward due to opiate receptors in NS.