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PSYCHIATRIC DISORDERS

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					PSYCHIATRIC
DISORDERS
PSY 3720
PSYCHIATRIC DISORDERS

 THE TOLL OF PSYCHIATRIC
  DISORDERS IS HUGE.



 AMERICAN STUDIES.

   NIMH.
PSYCHIATRIC DISORDERS

 EPIDEMIOLOGIC CATCHMENT AREA
  STUDY (NIMH).

 COMPREHENSIVE LOOK AT THE
  PSYCHIATRIC HEALTH OF THE
  UNITED STATES.
HIGHLIGHTS (NIMH)

  LIFE-TIME RATES FOR PSYCHIATRIC
   DISORDERS RANGE FROM 28-28%.

  SEX DIFFERENCES.

  WITHIN A 6 MONTH PERIOD 20% OF
   ADULTS SUFFER AT LEAST ONE OF
   THESE DISORDERS.
NATIONAL COMORBIDITY
STUDY
 50% OF POPULATION REPORT AT
  LEAST ONE LIFETIME PSYCHIATRIC
  DISORDER.

 30% reported at least one in a 12 month
  period.
SCHIZOPHRENIA

 Emil Kraeplin’s (1919) book became the
  cornerstone of this field of study.

 He searched for coherent patterns in the
  many symptoms of psychiatric disorders.

 He argued that schizophrenia fit into
  several distinct clinical forms.
KRAEPLIN

 Features common to the varied forms of
  schizophrenia include bizarre
  disturbances in thought, paranoid and
  grand delusions, auditory hallucinations,
  and an odd array of emotional changes.

   Thought disorder begins during adolescence
    and moves relentlessly to a chronic state of
    cognitive impairment.
EUGEN BLEULER

 Introduced the term schizophrenia.

 He examined more closely the underlying
  psychological processes of the disorder.

 Identified the key symptom as
  dissociative thinking (a major impairment
  in the logical structure of thought).
SCHIZOPHRENIA

 During the 1980’s and 1990’s
  researcher’s continued to refine
  diagnostic and descriptive categories so
  that both convey a common
  understanding of the basic features and
  withstand the rigors of reliability
  assessments.
SCHIZOPHRENIA

 DSM-IV.

 DIAGNOSTIC AND STATISTICAL
  MANUAL OF MENTAL DISORDERS.
SCHIZOPHRENIA

 Some have argued for a major division of
  symptoms into two separate groups.

 Positive symptoms.

 Negative symptoms.
GENETIC
CONTRIBUTIONS

 Family studies.

 Twin studies.

 Adoption studies.
GENETIC
CONTRIBUTIONS
STRUCTURAL CHANGES
IN THE BRAIN


 VENTRICULAR ENLARGEMENTS.
VENTRICULAR
ENLARGEMENTS
STRUCTURAL CHANGES
IN THE BRAIN


 LIMBIC SYSTEM ABNORMALITIES.

   Pyramidal cells in hippocampus of chronic
    schizophrenics were reported to be
    disorientated.
LIMBIC SYSTEM
ABNORMALITIES
REGIONAL AND CELLULAR
ABNORMALITIES

  Altered gene expression relevant for
   inhibitory neurons.
STRUCTURAL CHANGES
IN THE BRAIN

 Hypofrontality hypothesis.
HYPOFRONTALITY
THE DOPAMINE
HYPOTHESIS

 1) Amphetamine psychosis.

 2) chlorpromazine.

 3) Parkinson’s.
THE DOPAMINE
HYPOTHESIS

 Criticisms of this model have emerged.
ALTERNATIVE MODEL


 Alterations in the prenatal development
  of the hippocampus and/or amygdala
  may be a critical event in the overall
  etiology of schizophrenia.
ALTERNATIVE MODEL


 Some combination of GDE factors would
  alter the development of hippocampus
  and/or amygdala and their functional
  relationships to the rest of the brain.
RAT MODELS
 Several developmental rat models of
  schizophrenia have been developed.

   Idea is that hippocampus and/or the amygdala are
    altered early during brain development and that this
    event fundamentally alters the organization of the
    brain in adulthood.

   Leading to the symptoms associated with
    schizophrenia.
RAT MODELS

 Changes include alterations in areas like
  the nucleus accumbens and prefrontal
  cortex.

 Changes in the relationship of the
  hippocampus and amygdala to these and
  other brain regions.
RAT MODELS

 Neonatal lesions of the ventral
  hippocampus or amygdala.

 Lead to the emergence of abnormalities
  in various behaviours in adulthood.
RAT MODELS
 Abnormalities include:

   enlarged ventricles.

   increased action of postsynpatic dopamine
    receptors.

   Morphological changes in prefrontal cortex.

   Related deficits on tasks sensitive to prefrontal
    cortex function.
Memory                     Amygdala
             Striatum                   Hippocampus
Systems
(balanced)




GDE
factors

                             Nucleus
Other         Prefrontal    Accumbens
               Cortex                    Brainstem
Neural
                                           nuclei
Systems
  Memory                         Striatum                Hippocampus
 Systems
              Amygdala
Interaction

                                                                       Schizophrenia


                            Neonatal lesion/DA changes
 GDE
factors


               Prefrontal           Nucleus
 Other          Cortex             Accumbens        Brainstem
 Neural
                                                      nuclei
Systems
SUMMARY


 According to this model the alterations in
  dopamine-related behaviour and
  prefrontal function are a secondary
  consequence of prenatal alterations in
  learning and memory systems.

				
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