Explanations of phobic disorders

Biological explanations
1. Biochemical
  1. GABA - neurotransmitter released in response to high levels of arousal
    1. Inhibits Anxiety
      1. Low levels means excited neurons are not restrained
    2. Cowley et al - BZs (GABA substitute) used to decrease anxiety & arousal. Effects only short term
  2. Amygdala & Hippocampus - activated in response to stress
    1. Part of the ancient brain activated in emotional situations
    2. Tilfors et al - PET scans show phobics have increased blood flow to the Amygdala
    3. Furmark et al - Citalopram used to decrease Amygdala blood flow, successful treatement
    4. Not all phobics show increased blood flow
    5. High levels of noradrenaline (produce stress reponse) can damage Amygdala & Hippocampus
2. Genetic
  1. Family studies
    1. Fyer et al - probands (first to seek diagnosis for genetic disorder) have x3 many relatives with phobias compared to control
      1. Ost - 64% blood phobics had at least one relative with the same phobia
    2. Solyom et al - 45% phobics had at least one relative with a phobia compared to 17% in control
    3. Fyer et al - 31% first degree relatives diagnosed with phobia - only 2 were the same
      1. Genetic explanation cannot explain discrimination between phobic stimuli
    4. Not all phobias have the same genetic inheritability
      1. Kendler et al - 67% agoraphobia, 59% blood/injury, 51% social phobia, 47% animal phobia
        Torgerson - only 31% agoraphobia concordance in MZ twins. No concordance in DZ twins
    5. Brown et al - phobias more common in African-American than White populations. Cultural factors are important
    6. Diathesis stress model, individuals predisposed genetically, switched on by environment
  2. Twin studies
    1. Torgersen - MZ x5 more likely to have anxiety phobia with panic attack than DZ
      1. MZ twins more likely to share similar experiences than DZ twins, more interests even when brought up apart. Interests have a genetic tendency
  3. Inherited tendencies
    1. High arousal in the ANS causes high levels of adrenaline - oversensitive fear response
      1. Beta blockers a successful treatment reducing anxiety
    2. Dopamine pathways make you more readily conditioned, easier to develop phobias
      1. Tiihonen et al - lower number of dopamine receptors in social phobics
        Differences don't necessarily cause phobias, may be symptoms caused by phobias
    3. Abnormal Serotonin levels
  4. Phobia develops if an individual is genetically predisposed
3. Evolutionary
  1. Biological preparedness - phobias provided our ancestors with an adaptive advantage, more likely to survive & pass on phobic gene
    1. Cook & MIneka - easier to condition monkeys to fear toy snakes than teddies or toy rabbits
    2. Ohman - easier to condition humans to fear snakes than flowers
    3. Phobias linked to ancient fears fears, modern things not round long enough to provoke phobic response i.e guns & electricity
    4. Rapidly learn association between life threatening stimuli & fear - difficult to extinguish
      1. Mineka et al - monkeys develop snake phobia if they see another monkey showing fear. Same effect not seen for flowers
  2. Prepotency - tendency to response after a direct experience i.e anxiously to snake like movement
    1. Anxiety after an event not an evolutionary advantage therefore response developed to potential threats
    2. Ohman & Soares - snake phobics had greater fear response to masked pictures of snakes than non phobics - evidence for prepotent signals
  3. Merckelbach - most clinical phobias non-prepared not prepared
  4. Davey - phobias develop from expectancy bias of future negative consequences, not an evolutionary link. Explains modern phobias
Psychological explanations
1. Psychodynamic
  1. Phobias are a conscious expression of repressed conflicts
    1. Dealt with by the ego repressing undesirable memories into the unconscious
      1. Repressed memories can be projected onto neutral situations, not the real fear
  2. Freud - little Hans developed a horse phobia as he was scared his mother would leave him. Projected this onto phobia
    1. Unique individual, case studies cannot be generalised
    2. Lacked objectivity, His father & Freud interpreted evidence based on their beliefs on the origin of phobias
    3. Can be explained by classical conditioning
  3. Bowlby - agoraphobes often had early family conflicts. Leads to separation anxiety. Suppressed & reappear as agoraphobia
  4. Whiting et al - phobias more common in cultures with structured child rearing. Stricter parenting may lead to repressed desires
2. Behavioural
  1. Classical conditioning
    1. Little Albert developed a phobia to white furry objects
      1. Conditioned to fear white rat
        Stimulus generalisation
        Feared father christmas & rabbits
    2. Sue et al - phobics often can recall a specific incident causing the phobia, i.e being bitten by a dog
      1. Ost - not all phobics can remember a first experience, memory may have been repressed
    3. Bergman - failed to condition infants to fear wooden blocks, may only be ancient phobias such as animals - biological preparedness
  2. Operant conditioning
    1. Two process theory - phobias acquired through classical conditioning & maintained by operant conditioning
    2. Avoidance of stimulus reduces fear & provides negative reinforcement
  3. Social learning
    1. Phobias can develop observing others having a phobic response
      1. Behaviour is imitated
      2. Child develops phobia observing parents and copies as behaviour seems rewarding
    2. Bandura & Rosenthal - participants saw a confederate receiving 'shocks' when a buzzer sounded. Emotional reaction to the sound developed
    3. Different phobias have different roots, agoraphobia from a specific incident, arachnophobia from modelling
    4. Culturally most people are scared of snakes yet few have seen them
  4. Can account for cultural differences, culture specific role models can influence phobia development
3. Cognitive
  1. Phobias develop due to irrational thinking
    1. Can come from a traumatic experience
    2. Exposure doesn't initiate phobia, irrational thoughts do
  2. Beck et al - irrational thoughts create anxiety, fear of being in a high anxiety situation creates a phobia. Phobics often overestimate fears
  3. Phobics more likely to overestimate risks, predisposed to develop phobias because of cognitive style
  4. beck et al - phobics felt anxiety close to a stimuli but not far away, anxiety increase the closer they got
    1. Phobics more scared of the fear of fear, not the object itself

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Explanations of phobic disorders

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	Criado por Brendan Williams mais de 10 anos atrás