Phobia

1
Phobia Biological Theories
www.psychlotron.org.uk

• The anxiety response in phobia involves the same
  structures processes responsible for the stress
  response
• Some researchers suspect that phobia involves
  abnormalities in these structures processes

2
NS Reactivity
www.psychlotron.org.uk

• Liebowitz et al (1985)
• Gave social phobics and controls air with
  increased CO2 content to stress them
• Social phobics panicked significantly more often
  than controls
• These and many similar results suggest that some
  types of phobia involve hyper-reactivity of the
  sympathetic NS

3
Amygdala Abnormalities
www.psychlotron.org.uk
Source Hairiri et al, 2002
Amygdala

• Part of the limbic system
• Involved in processing of fear startle stimuli

4
Amygdala Abnormalities
www.psychlotron.org.uk

• Pine (1999)
• Compared amygdala responsiveness in social
  phobics and normal controls
• Found that social phobics had more responsive
  amygdalae
• Suggests that phobics may be more susceptible to
  fear-evoking stimuli

5
Amygdala Abnormalities
www.psychlotron.org.uk

• Hariri et al (2002)
• Compared PPs with different types of 5HT
  receptors
• Examined right amygdala responses to
  angry/fearful faces
• Abnormal receptor group were significantly more
  responsive

Source Hairiri et al, 2002
6
Conclusions
www.psychlotron.org.uk

• Genetic research suggests that phobia
  susceptibility may be inherited
• Some phobias appear more heritable than others
  (e.g. blood-injury social)
• Some phobias (esp. social) may be linked to
  abnormally responsive sympathetic NS and
  hyper-reactivity to fearful stimuli