Rep36 Understanding Personality Disorder

2.2 Causes of personality disorder

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personality disorder. There is a hypothesis that
temperament and character are expressed
through different memory pathways, suggesting
temperament is unconscious and character
conscious. However, as temperament and
character are linked, it suggests strong links and
connections between these memory pathways. 
2.2.1c Neuroanatomical and biochemical factors
Research in neuroanatomy has shown particular
connections between the development or
stimulation of areas of the brain and particular
emotional difficulties. The hypothalamus has
been associated with the development of
problems with anxiety (Gray, 1982). Studies using
Magnetic Resonance Imaging (MRI scanning)
have indicated that violent and impulsive
behaviour is associated with dysfunction in the
interior frontal cortex and the amygdala
(Hoptman, 2003). Psychopathy has been linked
to deficits in emotional processing, which has
been associated with the amygdala (Blair & Frith,
2000). Research in brain biochemistry has shown
we inherit ‘chemical templates’ that produce and
regulate proteins involved in the structure of the
nervous system and the neurotransmitters,
enzymes and hormones that regulate them
(Zuckerman, 1995). Therefore, we are not born
impulsive sensation seekers or antisocial
personalities but have differing levels of reactivity
to stimulation of brain structures and an
individual ‘chemical template’. 
2.2.2 Psychological factors in personality
disorders
Studies looking at genetic factors in the
development of personality traits suggest that
genetic variables account for up to 50 per cent of
the components of personality. The factors of
the environment that contribute to the remaining
50 per cent, would appear to come from the
‘unshared environment’ (Dunn & Plomin, 1990),
which would indicate that the environmental
factors involved in the development of personality
disorders do not primarily relate to being raised
within a particular family. Therefore, whilst some
personality traits are strongly heritable and the
development of personality disorders would
appear to be genetically influenced, researchers
generally accept environment plays a major role
in the development of personality disorders
(Paris, 1996).