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Describe and Compare Relative Strengths and Weaknesses of Explanations From the Biological and Learning Approaches

  • Both explanations can be tested with animal studies
  • However, data gained from animal studies is hard to generalise to humans
  • Neither explanation can give reason as to why some people are more likely to become addicted to a substance than others
  • The learning approach can explain why someone first started to take drugs whereas the biological approach doesn’t and explains how the addiction occurs
  • The biological approach can be scientifically tested e.g. PET scanning, whereas the learning cannot as it doesn’t explain the effects of a drug on the body
  • Biological approach gives evidence for the nature argument – Klien et al 2008 said there is a genetic link to experiencing withdrawal from heroin
  • Learning approach gives evidence for nurture argument – Morton et al 2001 said more involved parenting was linked to lower risk of drug use
  • Biological approach cannot explain cultural differences – learning approach can suggest how our surroundings can affect the likelihood of becoming a user e.g. it is legal in Holland
  • Withdrawal symptoms support the biological explanation as the brain is relying on the drug to function normally – withdrawal cannot be explained through the learning approach
  • Biological explanations allow us to understand physiological dependence better than learning explanations
  • Learning explanations are better at allowing us to understand physical dependence as they deal with reasons the person may find it difficult to cope without a drug
  • Biological explanations can show how misuse can occur in people with no contact with other drug users as the explanation only requires exposure to the drug – learning explanation requires contact with others to act as role models

Heroin

Mode of action

  • Mimics endorphin
  • Body’s natural opiates
  • Inhibitory neurotransmitters
  • Occupy and block receptor sites for pain
  • Make us feel good through the stimulation of the dopamine reward cycle
  • During everyday activity, a moderate amount of endorphin is naturally produced , causing the release of dopamine and facilitating the reward systems within the brain
  • If the body is under stress/pain, receptors are stimulated and the level of dopamine increases
  • Lock onto brain’s receptor sites for pain
  • Heroin acts like a massive release of endorphin
  • Heroin floods the endorphin receptors
  • Large quantities of dopamine are released – activates the reward system and produces feelings of well-being
  • Heroin blocks GABA (blocks dopamine at the synapse) – dopamine floods

Short-term effects

  • Rapidly produces a feeling of euphoria – 7 seconds after injection (dopamine rush)
  • Analgesic effect – calm, aches and pains disappear
  • Depresses most of body’s activities
  • Breathing becomes slower and shallower
  • Heart rate slows – stays slow so lowers blood pressure
  • User feels sleepy and very relaxed
  • Peripheral blood vessels dilate – feel flushed, warm, and sweaty
  • When someone first takes heroin, they will feel like they want to vomit
  • Heroin depresses activity of vomiting centre in brain – feeling of nausea gradually decreases as effect of heroin builds up
  • Digestive system is underactive so user may become permanently constipated
  • Low sex drive

Tolerance

  • Develops very quickly
  • Griffiths, Bigelow, & Henningfield 1980 – tolerance can increase up to tenfold in 3 to 4 months
  • Regular users take a dose high enough to kill a non-user
  • Body believes the normal dopamine level is higher due to chemical changes in the brain – has to have a high level of dopamine to feel normal – dose increases each time to maintain same effect

Physiological dependence

  • Develops very quickly
  • One fix can produce withdrawal symptoms if more is not taken in 12 hours
  • Brain rapidly gets used to the influx of heroin
  • Increases as tolerance does
  • Established as the addict takes a fix to avoid the increasingly severe withdrawal symptoms
  • Get physiological dependence get greater, psychologically, the prospect of coping without a fix feels worse

Psychological dependence

  • Addict ceases to be concerned about maintaining contact with family or friends
  • Focus of life becomes finding their next fix
  • When not in immediate effects of a fix, the addict tends to become increasingly confused, anxious, restless, and possibly paranoid – can only be relieved with more heroin or treatment

Withdrawal

  • Severity of symptoms is directly related to level of addiction
  • Symptoms start 6 – 12 hours after last fix
  • Failure to take a fix means symptoms will increase
  • Addict becomes agitated and often very aggressive
  • Symptoms peak after 26 – 72 hours
  • Most symptoms are over in a week
  • Becomes agitated and restless
  • Alternate between feeling hot and cold
  • Chicken skin (goose bumps)
  • Breathing becomes short and jerky
  • May then sleep for up to 12 hours but will wake to:
  • Cramps
  • Vomiting
  • Diarrhoea
  • Sweating
  • Shakes
  • Twitching of limbs
  • Symptoms gradually subside

Alcohol

Mode of action

  • Depresses activity in brain by making GABA more effective
  • Slows down the speed of messages being transmitted between neurons
  • Reduced effectiveness of inhibitory mechanisms that ensure we behave in a socially acceptable way – exhibitionism
  • Anaesthetises nerve endings at noradrenalin synapses (trigger fight-flight mechanism) so they become less effective
  • Slows reflexes because of increased GABA
  • Dilates skin blood vessels
  • Blocks hormone that controls urination – urination increases

Short-term effects

  • Feel warm and look flushed (dilated skin blood vessels)
  • Slower reactions
  • Perception and speech (slurred) are affected
  • Reduces people’s inhibitions (affects social control areas of the brain)
  • Relaxed, confident behaviour (reduced effectiveness of inhibitory mechanisms)
  • Affects motor-skills and co-ordination (depression of activity in frontal lobes)
  • Dehydration (hormone controlling urination is inhibited) – as blood alcohol levels fall, urination increases – main cause of hangovers – brain can lose up to a fifth of its weight
  • Heart rate slows down
  • Vomiting

Tolerance

  • Alcohol affects behaviour rapidly
  • Short-term tolerance develops quickly – as blood alcohol levels drop, the individual feels sober before they actually are
  • Alcohol consumption stimulates the body to produce an enzyme that breaks down alcohol more quickly
  • In a few weeks, a drinker will need to consume around 50% more alcohol to achieve the same effect
  • Behavioural tolerance is largely a result of practice – individual becomes better at coping with side-effects and appearing less drunk

Physiological dependence

  • Characterised by a lack of concern for the type of alcohol consumed
  • In extreme cases, alcoholics are known to drink industrial alcohol which can cause death
  • Often want to start drinking early in the day as they have withdrawal symptoms – first drink alleviates these symptoms – fuels physiological dependence
  • Alcoholic cannot restrict their alcohol intake as the physiological need is constant – ,many are unable to stop on a particular day until they pass out
  • Lack of concern for amount of alcohol consumed

Psychological dependence

  • Relief at finding a drink
  • Getting access to alcohol is put above other activities e.g. eating, socialising, maintaining hygiene
  • Many consume excessive amounts because of problems in their personal lives and alcoholic oblivion is welcomed as a coping strategy
  • With increased use, an alcoholic becomes psychologically dependent upon alcohol – see it as a way out of their problems

Withdrawal

  • Depends largely on level of use and addiction
  • Habituation to the level of alcohol is extremely fast both physiologically and psychologically within a drinking bout
  • Following drinking, the feeling of sobering up occurs much more quickly than the actual physiological process
  • Symptoms usually appear 8 – 12 hours after the last drink – can take as long as a week
  • Individual will become agitated and may have a range of other symptoms including:
  • Uncontrollable shaking
  • Cramp
  • Nausea
  • Sweating
  • Irregular heartbeat
  • Vivid dreaming
  • Symptoms can last up to 48 hours
  • For people with a heavy addiction, the effects of withdrawal are known as delirium tremens (DTs) – not uncommon to experience them whilst still drinking – habituation is happening faster than the intake of alcohol so the alcoholic experiences withdrawal even whilst drinking
  • With DTs, the brain habituates to the effect of alcohol on GABA receptors and therefore has a less efficient GABA system
  • Unless enough alcohol is present to depress brain activity, the fight-flight mechanism starts operating at too high of a level, producing symptoms including hallucinations, tremors, delusions, and seizures
  • Untreated withdrawal is fatal in a third of cases
  • Even with early treatment, about 5% of patients are likely to die