DBB: 18 - Theories of addiction: dependency models

why do people take drugs

• experimentation

• pleasure

• medication

• circumstance - e.g. WWII pilots staying awake

• peer pressure

what are the 4 top positive reasons for alcohol use people describe

• increase feeling of sociability

• makes me feel euphoric

• enables me to go along with friends

• enables me to experience different states of consciousness

what are the top 6 negative reasons fro alcohol use people describe

• relieves anxiety or tension

• makes me less inhibited

• makes me less inhibited sexually

• enables me to stop worrying

• alleviates depression

• makes me less self-conscious

what are the two opposing views for alcohol use

• disease model: addicts are victims of a chronic brain disease that leads to difficulty stopping

• failure of choice/moral failure: addicts are people who choose drugs (over family, health) because they are selfish, weak, antisocial, irresponsible

give an example of why these might co-ocur as time goes on

idea that most people drink (but why) → but most people dont get addicted (so maybe its something outside of peoples control)

what is support for the disease model and how does it explain relapse rates

when you look at a healthy brain Vs diseased → there is decreased activity in diseased

• ideas of relapse rates for drugs are similar to other diseases (asthma, diabetes) → same prognosis, hence addiction is a disease)

what is an opposing view on relapse rates for drugs

if you look at remission rates in wider population (like will get high relapse rates in people who received treatment and were administered)

• in this case, remission is actually quite high (in all age groups)

• drug dependence Vs average psychiatric disorders is a lot higher in comparison

what’s an example of drug use in soldiers in Vietnam

soldiers who went to Vietnam (where opioid use is high) many started taking them when deployed

• most reported being addicted while out these

• but when they come back most go into remission (but obviously addicted ones go into treatment)

what does this tell you about set and setting

how important it is for drug use

• can’t just understand addiction from the drug alone - need the set and setting to get the whole complete picture

• massive determinant

define addiction

a syndrome manifested by behavioural patten in which the use of a drug is given higher priority than other behaviour that once had higher value

at the extreme the dependence syndrome is associated with compulsive drug using behaviour

explain negative reinforcement models

drugs serve to increase the probability of further drug-seeking and drug-taking behaviour

• because of their ability to alleviate unpleasant states

how does this apply to food - what is drive theory

food promotes food-seeking and eating as it alleviates aversive states if hunger

• excitatory potential (sEr) = habit strength (sHr) X drive strength (D)

what is the self-medication hypothesis

drugs are used to self-medicate (relive symptoms that occur independently from drug use)

• usually com orbit with psychiatric disorders

• people who have a drug disorder/dependency → more likely to have mood disorder/anxiety

what is the physical dependent hypothesis

with the development of tolerance and physical dependence drug use is sustained in order to avoid the unpleasant consequence associated with withdrawal

what are distress syndrome reduction theories

people who continue to take drugs to ease ‘distress’ syndrome associated with cessation of drug use

• perhaps due to adaptations in brain reward systems or opponent process

• but withdrawal is typically transient

why was conditioned withdrawal model of drug addiction proposed - what does it explain

because many people (opioid addicts) report feelings if withdrawal when in therapy even after physical dependence has been gone for a while (as they’re talking about it)

• explains why people who are in remission for months, years may still relate → because of the brain process involved in learning

what are the four basic tenets:

1. withdrawal produces aversive state

2. drug use rapidly relieves withdraw

3. withdrawal is ‘conditionable’, through Pavlovian conditioning, to internal and external cues

4. conditioned and unconditioned withdrawal act to stimulate drug-seeking behaviour

explain the seitan experiment on heroin

rats placed in 3 groups:

• 1: given morphine and withdrawal in same test environment

• 2: given morphine and withdrawal in home environment

• 3: no morphine given

found:

• high response when expose to environment → not even when exposed to drug

• don’t see withdrawal symptoms really at all when tested in new environment

how is environment important for drug use in relation to lethality

drug tolerance can be specific to particular context → taking the same amount in a new place is lethal (found with heroin use)

• conditioning (CS) can evoke drug like or drug opposite effects

what’s a study that explains this

rats were give high doses of drug (alcohol, barbs, heroin)

• rats who never had drug → high rate of death

• dependent rats, but in a new place → less high rate but still high

• dependent rats, but in same place → less high than both

explain the study with monkeys and morphine self-administration

nalorphine (antagonist) induce withdrawal in dependent subjects

trained with flashing light 10 minutes before nalorphine injection (US) and 30 minutes after

• tested with flashing light (CS)

found:

• large increase in morphine taking after nalophine injection and during 30 minutes following light

• association of red light with precipitated withdrawal syndrome which enhances morphine taking

what aer some strengths for the conditioned withdrawal model

• can account for (long-term) relapse

• could apply to any drug which has a withdrawal syndrome

what are some weakness of the conditioned withdrawal model

• cannot explain the maintenance of drug taking before physical dependence

• not all drug cues trigger (physical) drug-opposite/withdrawal signs e.g. cocaine

• no straightforward explanation why they’re is selective conditioning to withdrawal effects

define homeostasis

organisms maintain equilibrium in all systems, including brain reward systems, to function within appropriate limits of physiology

• negative feedback = a process whereby the effects produced by an action serves to diminish or terminate that action

what is the opponent process model of addiction (conditioned opponent process model)

taking drugs to counteract negative effects (reach homeostasis - maintain balance)

• drug gets you high → when it stops → give you the full drop/opposite effect → cycle

what is the homeostatic model of motivation

stimulus (drug) triggers A-process which in turn triggers a slave B-process (negative feedback) that is opposite to A to re-establish homeostasis

• B is dependent on A → when A stops → B continues and overshoots (the low)

• repeated stimulation makes B-process, but not A-process, grow

• the A starts to draw out as B starts to overpower it

how can this process explain craving and relapse

• drug seeking cues can trigger (small) A and (large) B states to induce drug craving and release

• if cue is triggering A its also triggering B (aka the mini withdrawals people experience in remission)

explain the homeostatic dysregulation model based on this

neural system underlying A (reward) and B (anti-reward) process separate

• B continuously grows in addiction resulting in lowered (allostatic) set-point and permanent anhedonic state → spiralling

• progressively greater anhedonic/distress state ‘drives’ addict to seek and compulsively consume drugs

what are some neurological views on this

A-process = GABA, dopamine etc. going up

B-process = NPY (the stress response) which makes you go down, and gets bigger

what is the hypothesis that the B-process is the CRF system

increases are seen in extracellular CRF levels in the central amygdala during withdrawal from cocaine and ethanol

• increase in heart rate, blood pressure, behavioural response to stressors etc.

what’s a study to support this

rats with a history of cocaine or alcohol taking require higher electric current for brain self-stimulation suggesting a state of anhedonia

• more willing compared to controlled to give themselves brain shocks when in withdrawal → higher threshold in response to choking before responding (aka craving drug/sensation)

• so turn up threshold to overcome the aversive effects of withdrawal

what are the 4 views of addiction from negative reinforcement

• self-medication hypothesis: addicts take drugs to relieve (pre-existing) or medicate aversive state (e.g. co-morbidity)

• conditioned withdrawal hypothesis: cues trigger physical or psychological ‘mini-withdrawals’ that lead to drug taking

• conditioned opponent-process theory: aversive B-process

• Allostasis theory of addiction: spiralling aversive state by change in ‘setting-point’

what are some weaknesses to these views

1. drugs of abuse vary dramatically in how much withdrawal they produce

2. while cues associated with opiate abuse produce drug-opposite reactions, this is not seen for other abused drugs

3. many opiate addicts deny feeling conditioned withdrawal, and those that do often deny that this provides relapse

4. there is a poor correlation between craving and the occurrence of withdrawal or conditioned withdrawal