Biological Explanations of Phobias


  • Psychological disorders are caused by the same biological factors as pshysiological disorders.
  • The medical model of abnormal behaviour is that mental disorders are caused by something  "going wrong" with normal  bodily functions
  • Some of us inherit a gentic predispoistion to become anxious
  • Anxiety is caused by disrupted biochemistry or any other abnormal brain activity

3 Main ways of investigating genes

  • Family History
  • Twins Studies
  • Adaptation Studies
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Family History studies

Solyom et al (1974)-a study of 47 phobic patients found a family history of phobic disorders in 45% of the cases in contrast toonly 19% in families of a non- phobic control group of patients

Noyes et al( 1986)- Found a higher than normal rate of agoraphobia (12%) and panic disorders (17%)in first degree relates using the family interview method compare to other types of disorder

Last et al(1991)- the researchers found that a significantly higher proportion (35%) of the first degree relatives of people with an anxiety disorder also had an anxiety disorder compare to only 25% of relatives of people with an non axiety disorder

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Twin Studies

Torgersen (1983)-  found a 31%concordance rate in 13 MZ twins for panic disorders and agoraphobia compared to zero concordance in 16 DZ twins. However non of thw twins shared the same phobia 

Kendler et al (1992)-Found that MZ twins had a significantly lower concordance rate for agoraphobia than DZ twins. The Research suggests that this might reflect a protectve effect of the emotional bond between MZ twins

This study shows that both twin and family studys cannot be taken at face value. It is difficult to seperate the effects of genes and the environment 


Another genetic feature in the development if anxiety disorders may have to do with the temperment that the child was born with.Those who are socially inhibited in early life are more likely to go on to develop anxiety disorders in later life

Kagan et al(1988)-children that were socially inhibited from 2 years old to 7 years old. it is therfore possible that some people are born with anxiety related impairments 

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Biological Preparedness

Rosenhan and Seligman (1984)- proposed that there is an interaction between genes and conditoning that biologically predisposes us to aquire phobias towards certain types of stimuli.

We are genteically prepared to fear thing which were a source of danger to us in our evolutionary past. e.g. snakes, spiders, heights. There is a greater incidence of these phobias than of phobias of guns and knifes, even though these objects are potentialy as harmful as snakes and spiders.

Seligman (1971)- agrues that humans are prepared by the process of natural selection to fear certain things that were likely to cause us harm in our evolutionary past.

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Evaluation of Biological Preparedness

  • Cook and Mineka(1989)- found that monkeys quickly learned the phobia of snakes by watching other monkey show fear towards them, however they did not learn a phobia of fake flowers after watching other monkeys show fear towards them. This study shows that phobias can be learned through observation and that there is a genetic tendency to develop certain types of phobias. This supports biological preparedness
  • The fact that there are more phobias of insects comparent to non natural stimuli does not nessarily imply a gentic predispositon to fear certain objects in based on our evolutionalry past. Learning processes rather than genetic elements may account for such fears(SLT) 
  • The theory cannot account for individual diffrences. Seligmans theory of Biological preparedness cannot explain why some people have extreme and bizzare phobias of certain harmless stimuli such as shirt buttons or even oneself, similarly it cannot explain why certain people have no fear of potentially harmful situaltions and objects.
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Biochemical Explanations

GABA is a neurotransmitter that binds to receptors and inhibits neuron activity, therfore decreaseing neurone activity and decreasing anxiety

Studies of people treated with Benzodizapenes work like GABA and bind to receptors and decreses arousal and anxiety .PET scans show that people with phobias have an increased blood flow to the amygdala. when people with a specific phobia were exposed to the phobic stimulus increased activity in the amygdala was observed.


  • Successful treatment using the drug citoprom or CBT has shown to reduce blood flow in amygdala
  • Not all people show an increase in blood flow to the amygdala and it is not clear wheter they are a casual factor or result of a phobic disorder.
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Biological Therapies for Phobias

  • Psychological disorders are caused by the same biological factors as physiological disorders. The medical model of abnormal behaviour is that mental disoders are caused by abnormality in normal bodily functions e.g. an imbalance in neurotransmitters.
  • Biological treatments are designed to correct this imbalance through the administration of drug treatments.ECT, or psychcosurgery.
  • Benzodizapienes mimc GABA and provide an inhibitory function in the nervous system and produce muscle relaxation e.g. Librium and Valium
    • Doctors in the 50's and 60's found that they were apparently a safer way to reduce anxiety in patients as they did not cause fatalites when overdoesed 
  • Anti- anxiety drugs are often used in combination with behavioral therapy to reduce panic attack symptoms.
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