Phobias

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  • Created on: 28-05-15 10:07

Classification and Diagnosis of Phobic Disorders

Validity: Refers to the extend that a diagnosis represents something that is real and distinct from other disorders and the extent that a classification system such as ICD

  • Comorbidty: Refers to the extent that two conditions co-occur

Kendler et al: Research has found high levels of comorbidty between social phobias, animal phobias, generalised anxiety disorders and depression 

  • Concurrent: Establishes value of a new measure of phobic symptoms by correlating it with an existing one. 

Herbert et al: Established concurrent validity of social phobia anxiety inventory (SPAI) by giving the test and various other standard measures of 23 social phobics - SPAI correlated well with other measures

  • Construct: Measures extent that a test for phobic disorders really does measure a target construct of phobias

Clinicians identify possible target behaviours that we would expect in someone with a phobic disorder and see if people who score high on the test for phobic disorders also exhibit target beahaviour. 

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Classification and Diagnosis of Phobic Disorders

Evaluation

  • Comorbidty: Eysenck reported that up to 66% of patients with one anxiety - The implication is that a diagnosis should simply be 'anxiety disorder' rather than a phobia
  • Concurrent: Mattrick and Clarke showed their social phobia scale correlated well with other standard measure. This indicated there are methods of diagnosis that agree - measures that something is real
  • Construct: Beidel et al: SPAI correlates well with behavioural measures of social phobia but doesn't correlate well with behaviours related to other anxiety disorders. 
  • Implication of low reliability/validity: Researchers require a reliable and valid means ofassessing disorders in the first place
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Classification and Diagnosis of Phobic Disorders

Reliability: Reliability of such questionnaires or scales can be measured in terms of whether two independent assessors give imilar scores (inter-rater) or whether the test items are consistent (test-retest) 

  • Inter-rater: Skyre: Asked 3 clincians to assess 54 patient interview obtained using structured clinical interview. They found high inter-rater agreement (+72) = reliable
  • Test-retest: Scales such as SCID takes 1-2 hours to complete. The alternatice is to use shorter, structured, self-administered sclaes. 

Popular for specific phobias: For example Hiller et al - MDC reported satisfactory to excellent diagnostic agreement in test-restest using MDC

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Classification and Diagnosis of Phobic Disorders

Evaluation:

Research Evidence: SCID requires extensive training which may explain high reliability

  • Kedler et al used face-to-face and telephone interview over a one month interval (test-retest) and found a mean agreement of +46. Over long term (8 years) found a mean agreement of +30

Reasons for low reliability: Kendler et al: test-retest reliability might be due to the poor recall by participants of their fears - people tend to over-exaggerate fears when recalling previous distress. 

  • Low inter-rater reliability might be due to different decisions made by interviewers when deciding if the severity of a symptom does or does not exceed the clinical threshold for a symptom.
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Biological Explanations of Phobic Disorders

Evolutionary Factors: 

Ancient Fears: Some stimuli are more likely to be feared than others - snakes, heights, storms: reflected real danger to our ancestors 

Prepotency: Natural selection has shaped our nervous system so that we attend more to certain cues than others - something that has power prior to direct experience

Preparedness: Humans are biologically prepared to rapidly learn an association between particular stimuli and fear. This association is difficult to extinguish

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Biological Explanations of Phobic Disorders

Evaluation: 

Prepotency: Ohman and Soares: Masked picture were constructed of feared objects so they were not easily recognisable. Participants who were fearful of snakes showed greater GSR when briefly showed masked photos - prepotent signals

Preparedness: Mc Nally concluded that there was firm evidence for changed resistance to the extinsion of fear responses conditioned by 'prepared' stimuli 

Clinicial Phobias: Much of the research is concerned with avoidance responses rather than clinical disorders - Merckelbach found that most of clinical phobias were rated as non-prepared rather than prepared

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Biological Explanations of Phobic Disorders

Genetic Factors

Family Studies: Fyer et al: Found that probands had 3 times as many relative who also experienced phobias as normal controls

  • Solyom et al: Found that 45% of phobic patients had a least one relative with the disorder, compared to a rate of 17% of non-phobic controls

Twin Studies: MZ twins are genetically identical a closer concordance rate between MZ and DZis evidence for a genetic basis

  • Torgersen: Compared MZ and DZ twin pairs where one twin had an anxiety disorder - such disorders were 5x more frequent in MZ 

What is inherited? Oversensitive fear response - explained in terms of the ANS. There may be abnormally high levels of arousal in the ANS which leads to increased amounts of adrenlaline - adrenergic theory 

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Biological Explanations of Phobic Disorders

Evaluation: 

Family and Twin Studies: Torgerson only found 31% concordance for MZ twins in terms of anxiety disorders and almost not concordance for DZ twins - fails to control for shared environmental experiences

The diathesis stress model: Genetic factors predispose an individual to develop phobias but life experiences play an important rolein triggering such responses

What is inherited: Tiihonen foudn singinificantly lower number of such sites in patients with social phobias than in normal controls - the low number of sites lead to abnormal low levels of dopamine

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Psychological Explanation of Phobic Disorders

Behavioural

Classical Conditioning: Fears are acquired when an individual associates a neutral stimulus with a fear response - Case study of Little Albert

Operant Conditioning: Mowrer the 2nd stage of acquiring phobias - the avoidance of the phobic stimuli trduces fear and is thus reinforcing

Social Learning: May also be acquired through modelling the behaviour of others 

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Psychological Explanation of Phobic Disorders

Evaluation

Conditioning: Not everyone who has a phobia can recall such an incident. For example not everyone who was bitten by a dog  would develop a phobia suggested by the diathesis stress model - only those with a genetic vulnerablity would develop a phobia

Biological Preparedness: Phobias do not always develop after a traumatic incident - fear responses are only learned with living animals

Soical Learning: Bandura and Rosenthal suggested that a model experienced pain every time a buzzer sounded. Participants who observed this showed an emotional reaction to the buzzer 

Sue et al: Suggested that different phobias may be the result of different processes

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Psychological Explanation of Phobic Disorders

Cognitive: Phobias may develop as the consequence of irrational thinking

  • Aaron Beck proposed that phboias arise because people become afraid of situations where fears may occur
  • Tend to overestimate their fears

Evaluation

Dysfunctional assumptions: Gournaly found that phobics were more likely than normal people to overestimate risks - more fearful being more predisposed to develop phobias

Success of cognitive behavioural therapy: If a therapy changes the dysfunctional assumptions a person has and leads to a reduction in their phobia- then dysfunctional assumptions may originally have caused the disorder. 

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Psychological Explanation of Phobic Disorders

Psychodynamic: 

Freud: A phobia is the conscious expression or repressed conflicts. The ego deals with conflict by protecting itself and repressing emotions into the unconscious mind

  • Repressed conflicts = greater anxiety
  • Deals with this through dreams or displacing onto a netural object
  • Research Support: Little Hans
  • Bowlby: Found that agoraphobics often had early experiences of family conflict. He suggested that such conflict leads a young child to feel very anxious when separated from their parents

Evaluation: 

Little Hans: Only provided one piece of research, can easily be explained by classical conditioning - unique to the individual and cannot be generlaised.

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Biological Therapies for Phobic Disorders

Chemotherapy: 

Benzodiazepines: Slow down activity of central nervous systems by enhancing the activity of GABA - this has a quieting effect on many of the neurons 

Beta-blockers: Reduce the activity of nora/adrenaline - bind to receptors causing the heart to beat slower with less force - fall in blood pressure - less stress on the heart

Anti-depressants: SSRIs - increase the levels of serotonine which regulates mood and anxiety 

Evaluation: 

  • Not a cure: Drugs are not considered the primary treatment for phobias  - simply focus on the symptoms rather than the cause
  • Side Effects: Side effects of BZs include aggressiveness and long-term impairment of memory
  • Addiction: BZs are very addictive - as a result used a maximum of 4 weeks
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Biological Therapies for Phobic Disorders

Psychosurgery

Capsulotomy and Cingulotomy: Remove the capsule and cingulum - the connection with the organ are severed. Both part of the limbic system - irreversible

Transcanial Magnetic Stimulation: Insert a probe through top of the skull, pushes it into the capsule, the tip burns small portions of the tissue. 

Deep Brain Stimulation: Placing wires in target region of the brain - when the current is on it interrupts target circuitthus reducing symptoms 

Evaluation: 

  • Issues studying the effectiveness of drugs 
  • Substituting a placebo for an effective treatment does not satisfy this duty as it exposes individuals to a treatment known to be inferior
  • Informed consent: Not informed about comparative success of drugs versus placebos
  • Irreversible forms of psychosurgery 
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Psychological Therapies for Phobic Disorders

Cognitive Therapy: REBT

Ellis proposed that the way to deal with irrational thoughts was to identify them using the ABC model

A - Activating Event

B - Belief 

C - Consequences

Disputing: Focuses on challenging or disputing the beliefs and replacing them with effective rational beliefs

  • Logical Disupting: Self-defeating beliefs do not follow logically from information available
  • Empirical Disputing: Self-defeating beliefs may not be consistent with reality
  • Pracmatic Disputing: Emphasisesthe lack of usefulness of self-defeating beliefs

self defeating ------> rational 

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Psychological Therapies for Phobic Disorders

Evaluation: 

Not suitable for all: Ellis believed that sometimes people who claimed to be following REBT principles were not putting their revises beliefs into action and therefore was not effective

  • Some do not want the direct advice

Theorestical basis: Alloy and Abrahmson found depressed people gave more accurate estimates of the likelihood of a disaster than formal controls

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Psychological Therapies for Phobic Disorders

Behavioural Therapy: Systematic Desentisation

Counterconditioning: Begins with learning relaxation techniques - acquire a new stilumus - response link - responding to feared stimulus with relaxation. 

  • Taught how to relax their muscles
  • Construct desentisisation hierarchy -series of imagine scenes
  • Work way through hierarchy - visualising each event
  • Once mastered one step - ready to move on
  • Masters feared stimulus

Different forms of SD: 

  • Vivo - confront feared stimulus directly
  • Covert - Imagine presence of it
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Psychological Therapies for Phobic Disorders

Evaluation: 

Effectiveness: Mc Grath et al - reported that about 75% of patient with phobias to SD

Appropriateness: 

  • Symptom Substitution: May appear to resolve a problem but simply substitution/eliminating or supressing symptoms can result in other symptoms
  • Is relaxation necessary? Might be that the expectation of being able to cope with feared stimulus 
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