susceptibility models Flashcards
what are susceptibility models also referred to?
vulnerability or adaptive models
how do susceptibility models explain addiction?
- model places emphasis on individual
- suggests certain individuals are more at risk of becoming addicted
- due to individual having a vulnerability or addictive personality
what is the peak age for self-reported drug use?
- 18-20 years
- most commonly cannabis/marijuana
what does Anthony et al. (1994) findings show about the transition to drug abuse?
- transition is variable
- the % of exposed users is not a good predictor of the % becoming dependent
- transition to addiction is higher in some drugs than others
- e.g.: 32% of those exposed to nicotine become addicted but only 23% of those exposed to heroin become addicted
- suggests nicotine is more addictive than heroin
what factors influence susceptibility to addiction?
demographic factors
- prevalence of drug use in local area
- neighbourhood (crime rate, population)
- parental socioeconomic status
- criminality in family
- broken home
what factors influence susceptibility to addiction?
psychosocial factors
- mental health of parents
- poor parenting style (abusive, authoritative, inconsistent etc.)
- failure at school
- peer group social norms
Outline Tarter et al. (2003) study into psychosocial factors and drug use
- longitudinal study
- studies 12 y/o ‘high risk’ children of drug/alcohol dependent parents
- took measures of personality, temperament and cognitive capabilities
- compared high risk children to low risk children
- children were assessed again at age 16 and 19, including for drug use
- identified ‘neuro-behavioural dysregulation’ as greater in the high risk than low risk group
- this factor predicted the transition to drug use
what is ‘neurobehavioral dysregulation’? (Tarter et al., 2003)
classified as:
- difficult temperament (inflexible, distractible)
- conduct disorder
- oppositional defiant disorder
- ADHD
- depression
- disruptive behaviour
- measures of executive cognitive function
what did Tarter et al. (2003) conclude?
- those at risk of drug abuse show disorganised behaviour
- possibly stemming from an abnormality in frontal cortex that causes poor decision making
Explain the case study of Phineas Gage
(Harlow, 1868)
- suffered severe frontal lesion from iron bar going through FC
- after incident his personality changed in a negative way
- had poor decision making and planning abilities after injury
what is the frontal region of the brain known to be involved in?
conscious decision making
what is the Iowa gambling task?
- ppt presented with 4 virtual deck of cards on computer screen
- goal = to win money
- ppts told all cards results in some level of reward
- occasionally choosing some cards causes ppt to lose some money
- rewards are rigged
REWARDS
- $100 on average for choosing cards from decks A and B
- $50 on average for choosing cards from decks C and D
LOSSES
- deck A and deck B have total losses of $1250
- deck C and deck D have total losses of $250
- normally ppts work out that A and B are bad decks as they lead to long term loss
- C and D are good decks as they lead to long term gains
what does Bechara et al. (2000) show about decision making and a damaged frontal cortex
- conducted neuroimaging studies of decision making using Iowa gambling task
- task used to model real-life decision making
- frontal cortex usually involved in decision making tasks
- found that patients with lesions to frontal cortex were worse at Iowa gambling task than normal
- because they opt for high immediate gains despite higher future losses
According to Deakin et al. (2004) what contributes to increased risk taking in younger groups?
- late maturation of the frontal cortex
Why does the late maturation of the brain cause a problem for drug addiction?
- illicit drug use usually starts in adolescence
- peaks at 18-20 years old
what did Goudriaan et al. (2007) show with regards to susceptibility to risky decision making with lesions to frontal cortex?
- used the Iowa gambling task
- perseveration in selecting the high reward decks (despite the bigger future loss) is shown in a number of groups:
Those with:
- frontal lesions
- adolescence
- conduct disorder
- ADHD
- schizophrenia
- Drug users of all classes
what behaviour is seen in young children before any drug use?
- risky decision making
what effect does risky decision mean for drug use?
- helps predict the onset and magnitude of drug use
- suggests a susceptibility factor for becoming a drug user (Tarter et al., 2003)
what effect does prolonged drug use have on a user?
- damage to frontal cortex
- causing further deficits in decision making
- causing prolonged drug use
- sets up a vicious circle where existing frontal lobe deficits are worsened by drug use
what 3 abnormalities in decision making contribute to drug use?
- reward hypersensitivity
- punishment insensitivity
- faulty error detection
explain reward hypersensitivity
- midbrain dopamine cells increase in activity
- occurs when humans or animals consume natural rewards (food, water, sex)
- or drugs of abuse (nicotine, cocaine, heroin)
- suggests that drugs of abuse hijack brain substrates for reward/pleasure
- therefore, consumed because drug taking = positively reinforced
explain reward hyposensitivity
- suggested to be the maintenance of drug use
outline Kenney et al. (2006) study on rats and exposure to heroin
- rats exposed to heroin
- after being exposed chronically, rats showed an increased threshold in their brain dopamine reward system
- as rats needed more stimulation to achieve the desired effect, this suggests chronic drug use associated with a decrease in reward sensitivity (anhedonia)
- anhedonia motivated drug use as drugs improve mood through negative reinforcement
explain punishment insensitivity
where drug addict persistently uses drugs despite knowing the likely harms it would cause
addicts are insensitive to the punishing consequences of their actions
