exposure models

Question 1

what does the exposure model (Bardo et al., 1996) suggest about addiction?

Answer 1

all individuals are at equal risk of becoming addicted to drugs given sufficient exposure

Question 2

how does the exposure model suggest that individuals become addicted to drugs?

Answer 2

this is because drugs interact with and change the brain

changes to the brain as a result of drug use create continued motivation to use the drug

Question 3

explain the withdrawal model of addiction

Answer 3

• suggests addicts continue to use the drug to avoid withdrawal

Question 4

what is withdrawal?

Answer 4

physical or mental symptoms an individual experiences when they suddenly stop taking drugs

Question 5

how does negative reinforcement apply to withdrawal model of addiction?

Answer 5

• drugs = negative reinforcer
• drugs act as painkiller
• restoring addict to their ‘normal’ version
• avoids physical/mental effects of withdrawal

Question 6

how does positive reinforcement apply to withdrawal model of addiction?

Answer 6

• initial rush/high of taking drugs = positive reinforcement

Question 7

how does individual come to withdrawal?

Answer 7

• suddenly stopping drug
• taking drugs but initial high exhausts reward/pleasure centre in brain
• when drug wears off, user goes in to withdrawal

Question 8

Outline a key criticism of withdrawal models

Answer 8

• stopping drugs under medical supervision does not always result in long-term abstinence
• drug users often relapse even after undergoing supervised withdrawal

Question 9

Explain how withdrawal can be conditioned
(Wilker)

Answer 9

• proposed idea that withdrawal can be triggered by external cues
• exposure to cues = sufficient to elicit withdrawal causing relapse
• environmental stimuli consistently paired with withdrawal
• Pavlovian conditioning –> learned associations become triggers for withdrawal symptoms

Question 10

outline incentive model of addiction

Answer 10

• midbrain dopamine cells increase activity
• when humans/animals detect or consume both natural rewards (food, water, sex)
• or abuse drugs (nicotine, cocaine, heroin)
• suggesting drug abuse hijacks the brain substrate for reward/pleasure
• drugs therefore consumed because drug taking = positively reinforced

Question 11

what is the main assumption of Pavlovian Conditioning?

Answer 11

• learning through association
• conditioned response is reflexive stimulus-response habit
• require no conscious thought

Question 12

explain conditioned withdrawal

Answer 12

• suggests drug users often relapse due to environmental stimuli that is associated with drug use
• this becomes a trigger for withdrawal

Question 13

Outline a study investigating conditioned withdrawal
(O’brien et al 1977)

Answer 13

• looked at conditioned withdrawal in heroin addicts
• volunteers on methadone maintenance (used to help stop taking heroin) given low dose of naloxone (opiate blocker, used to reverse effects of opioids)
• this was to bring on opiate withdrawal
• opiate withdrawal demonstrated by reduced skin temperature
• injection of naloxone was paired with a peppermint odour in conditioning chamber
• injection of naloxone caused a sharp drop in skin temperature
• during saline test trials, peppermint alone produced temperature drop
• supporting idea that environmental stimuli can cause withdrawal/relapse

Question 14

Outline the opponent process model

Answer 14

• supports conditioning account of addiction
• proposes there can be opposing reactions to the same stimulus
• primary response will be followed by an opposite secondary response
• the predominant response can change over time
• this results in a shifting profile of manifest response
• with addiction, positive incentive reaction would be expected to predominate early on
• then drug-opposite reactions would be expected to have stronger influence on the manifest net response

Question 15

how does the opponent process model explain tolerance?
(Siegel et al., 1982)

Answer 15

• tolerance = occurs after long-term use of drug abuse so body becomes used to the drug. This means drug will stop having as much effect
• Siegel studied effects of high heroin doses given to heroin tolerant rats
• mortality % after giving heroin to heroin tolerant rats depended on environment
• mortality % in new environment = 96%
• mortality % in usual environment = 64%
• effect of environment shows that environmental cues associated with drug taking can elicit a ‘drug opposite response’
• drug opposite response may be aversive (disliked) if no more drug is taken so there is motivation for drug taking to alleviate this state

Question 16

identify a problem for negative reinforcement theories

Answer 16

• animals and humans rapidly learn to obtain drugs, in exactly the same way that they learn to obtain natural rewards such as food, water or access to a sexual partner
• suggests that drugs are taken in order to achieve the pleasurable high they produce
• suggesting drugs are positive reinforcers instead of negative reinforcers

Question 17

outline experimental evidence for drugs being a positive reinforcer

Answer 17

• rats will readily learn to press a level to self-inject a drug (i.e.: amphetamine)
• injected either directly into part of brain or into general circulation of blood

Question 18

Outline Hogarth et al. (2010) research into drugs being positive reinforcers

Answer 18

• reported data consistent with hypothesis that drug cues prime drug taking
• done by reminding addict of positive qualities of nicotine
• when neutral images were paired with cigarette, there were increased ratings of probability of taking a puff as well as increased pleasure and reduced anxiety ratings
• suggests that drug cues motivate drug consumption and are rated as pleasant rather than aversive