exposure models of addiction Flashcards
patterns of drug use, exposure models, withdrawal model, opponent process model (15 cards)
what are the patterns of drug use?
no concrete evidence - often sample bias
drug use is relatively stable over time
most illicit drug use isn’t daily
most drug use is by less affluent people
most drug use is by younger people
most drug use is by men
use patterns vary by age and drug
what are exposure models of addiction?
all people at risk of becoming addicted to drugs given sufficient exposure
drugs interact with and change the brain and these brain changes create continued motivation to use the drug
models differ in the explanation as to what sort of changes drugs produce in the brain and what sort of motivation drive subsequent drug use
what is the withdrawal model?
addicts continue to use the drug in order to avoid withdrawal
physiological and psychological symptoms occur when not doing the drug
what is withdrawal?
initial high exhausts the reward/pleasure regions of the brain and once the drug wears off the user goes into withdrawal
very aversive
a form of negative reinforcement
what are the issues with the withdrawal model?
relapse
can’t all be aversive
what is the “can’t all be aversive” issue with the withdrawal model?
midbrain dopamine cells increase activity when humans or animals detect or consume both natural rewards (food, water, sex) and drugs of abuse (nicotine, cocaine, heroin)
suggests drugs of abuse hijack brain substrate for reward/pleasure and are consumed because drug taking is positively reinforcing
what is the relapse issue with the withdrawal model?
stopping drugs under medical supervision does not necessarily result in long term abstinence
drug users often relapse despite having undergone supervised withdrawal from drugs
to explain this, Wickler (1948) proposed withdrawal can be triggered by external cues
conditioned withdrawal
what is conditioned withdrawal?
environmental stimuli (addict’s bedroom or living room) consistently paired with withdrawal
through Pavlovian conditioning, stimuli enter into learned associations to become triggers for withdrawal symptoms
subsequent exposure to these cues is sufficient to elicit withdrawal and therefore precipitate relapse
explain relapse following primary withdrawal
what is the trace phenomenon?
anecdotal reports from relapsed drug users suggest things are not always as predicted (by context in which withdrawal had occurred most frequently)
people can associate cues with outcomes over a delay or a trace
what is opponent process model?
initial positive experience = positively reinforcing drug use
subsequent negative experience = where body attempts to restore balance, leading to negative effect (withdrawal)
with repeated use, initial positive effects become weaker (tolerance) and negative effects become stronger
creates cycle of addiction
what is tolerance?
“after repeated use of a drug, the body’s response to the substance diminishes over time. This means that higher doses of the drug are required to achieve the same effect that was initially produced at lower doses. Tolerance can develop to various effects of the drug, including its therapeutic effects, side effects, or both” - ASAM
what is pharmacodynamic tolerance?
when drug’s effects at the cellular or receptor level become less pronounced
dopamine systems less responsive
what is pharmacokinetic tolerance?
when body becomes efficient at metabolising or eliminating the drug
body better at breaking down substances
e.g. drink more to become drunk
what is conditioned tolerance?
high heroin doses given to heroin tolerant rats
novel environment = 96% deaths
usual environment = 64% deaths
environmental cues associated with drug taking can elicit a “drug opposite” response
drug opposite response may be aversive and motivate drug taking to alleviate this state (negative reinforcement)
what is positive conditioning?
Hogarth et al (2010)
data consistent with hypothesis drug cues prime drug taking by reminding addict of positive appetitive qualities of drug (not by eliciting an aversive state)
