Biopsychology of Psychiatric Disorders

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Biopsychology of Psychiatric Disorders

• Schizophrenia

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What is Schizophrenia?

• Severe and debilitating condition
• Characterized by hallucination, delusion,
  emotional changes and bizarre motor behavior
• Distinction in symptoms Positive vs. Negative

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Genetics

• Genetic studies based on family histories, twin
  studies and adoption studies indicate a strong
  heritable component to schizophrenia.

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Neuropathology

• Ventricular enlargement
• Cellular disorientation
• Developmental problems in limbic system
  structures
• Other brain areas showing abnormalities include
  cerebellum and corpus callosum
• fMRIs reveal general decrease activation of the
  frontal cortex (i.e. hypofrontality hypothesis)

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Ventricular Enlargement in Schizophrenia
Rosenzweig et al., 2002
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Hippocampus in Schizophrenia cellular
disorganization
Rosenzweig et al., 2002
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• Hypofrontality in Schizophrenia
• during rest and during a card sorting test that
  requires cognitive flexibility

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Dopamine Hypothesis of Schizophrenia

• Schizophrenia-like states may be induced by
  amphetamine, which potentiates dopaminergic
  activity.
• Drugs that block dopamine (or neuroleptic drugs)
  ameliorate the symptoms of schizophrenia
• BUTthere is more to the story

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other neurotransmitters might be involved

• Some neuroleptic drugs also show an affinity for
  Serotonin
• PCP (phencyclidine) induces schizophrenia-like
  states and that involves Glutamate via NMDA
  receptor
• OR
• psychotogens might be involve abnormal
  substances formed from faulty metabolic processes
  (i.e. harmless molecules are turned into aberrant
  molecules) produce psychotic behavior.

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Infact

• Most antipsychotic drugs work on multiple
  neurotransmittersso which one(s) are implicated
  in schizophrenia?

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The Complex Nature of Antipsychotic Drugs
Rosenzweig et al., 2002
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Are you able to appreciate the complex nature of
psychiatric disorders?

• The reason that there are so many subtypes of a
  disorder?
• The reason that one drug might not be helpful to
  all people?
• That the flavor of the psychiatric disorder
  reflects the brain system(s) that are affected?
• How the environment, stress and neurobiology
  interact?

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Current thinking

• An integrative psychobiological model that
  emphasizes the interactions between environmental
  stressors (e.g. social situations) and brain
  abnormalities that predispose the individual to
  develop schizophrenia.

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Do you remember this from the first day of class?
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