BIOLOGICAL THEORIES

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BIOLOGICAL THEORIES
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REVOLUTION 1970s - PRESENT

• FROM
• PSYCHOLOGICAL
• PERSONALITY
• EARLY LIFE
• PSYCHOTHERAPY

• TO
• BIOLOGICAL
• DISEASE
• BRAIN
• MEDICATION

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HISTORY

• DOMINANT IN 19TH CENTURY - DISEASE OF BRAIN
• MOST OF 20TH CENTURY - LIMITED TO MENTAL
  HOSPITALS

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UP UNTIL ABOUT 1970

• RISE AND DOMINANCE OF PSYCHODYNAMIC THEORY
• LITTLE KNOWLEDGE ABOUT BRAIN
• DISCREDITING OF GENETIC THOUGHT WITH NAZIS

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EMERGENCE OF BIOLOGY

• SCIENTIFIC REVOLUTION BEGAN IN 1970s
• MORE KNOWLEDGE ABOUT BRAIN HUMAN GENOME PROJECT
  NOW
• NEW TECHNOLOGY FOR THE STUDY OF THE BRAIN (CAT
  MRI PET)

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EMERGENCE OF BIOLOGY

• PSYCHOPHARMACOLOGICAL DEVELOPMENTS
• INSURANCE AND MANAGED CARE
• DRUGS CHEAPER AND MORE EFFICIENT THAN THERAPY
• CAN TREAT SERIOUSLY ILL

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CONCEPT
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DSM-III (1980)

• REJECTED DYNAMIC MODEL OF DSM-I AND DSM-II
• ADOPTED DIAGNOSTIC MODEL

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DIAGNOSTIC MODEL

• NOT CONTINUOUS, BUT CATEGORICAL
• SYMPTOMS INDICATE UNDERLYING DISEASES

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PROBLEM W/CONCEPT

• NO GOLD STANDARD FOR UNDERLYING DISEASE
• CIRCULAR USE SYMPTOMS TO INDICATE DISEASE BUT
  ONLY KNOW IF DISEASE THROUGH SYMPTOMS

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CAUSES
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CAUSES

• BRAIN DISORDERS
• OFTEN GENETIC VULNERABILITIES
• EARLY CHILDHOOD ILLNESSES OR TRAUMAS
• CURRENT TRAUMAS CAN CHANGE BRAIN

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EVIDENCE FOR GENETIC

• PROBABILITY OF SCHIZOPHRENIA
• NO SCHIZ RELATIVES 1
• UNCLES/AUNTS/COUSINS 2-4
• ONE PARENT 6
• FULL SIBLING 10
• DZ 6-15
• MZ 30-40

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BASIC PROBLEM

• FAMILIES TRANSMIT GENES AND BEHAVIORS, VALUES,
  CULTURE, ETC.
• HOW SEPARATE GENETIC FROM ENVIRONMENTAL
  INFLUENCES?
• TWO MAJOR WAYS

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ADOPTION STUDIES

• GET GENES FROM ONE SET OF PARENTS AND ENVIRONMENT
  FROM ANOTHER SET
• NATURAL CHILDREN OF M.I. PARENTS RAISED BY
  NON-M.I. FOSTER PARENTS
• COMPARE TO ADOPTED CONTROL GROUP

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HESTON STUDY

• 47 CHILDREN BORN TO SCHIZ. MOTHER IN OREGON M.H.
  1915-45 AND TAKEN AWAY AT BIRTH
• CONTROL GROUP OF 47 CHILDREN OF NON-M.I. MOTHERS
  ADOPTED AT BIRTH

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HESTON (CONT.)

• 17 OF CHILDREN BORN OF SCHIZ. MOTHERS BECAME
  SCHIZ.
• 0 OF CONTROL GROUP
• OTHER STUDIES OF SCHIZOPHRENIA ALSO SUPPORT
  GENETIC INFLUENCE (ALTHOUGH NOT AS STRONGLY)

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OTHER ILLNESSES

• DEPRESSION AND ALCOHOLISM
• RATES IN ADOPTEES SOMETIMES RESEMBLE FOSTER
  PARENTS MORE THAN NATURAL PARENTS
• INDICATES ENVIRONMENTAL AS WELL AS GENETIC
  INFLUENCES

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TWIN STUDIES
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COMPARE MZ - DZ TWINS

• MONOZYGOTIC TWINS (MZ) - SHARE 100 GENES
• DYZYGOTIC TWINS (DZ) - SHARE 50 GENES
• RAISED IN SAME FAMILY, ETC.
• CONTROL ENVIRONMENT, VARY GENES

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DIFFERENCES IN SCHIZ.

• SIBLINGS 10
• DZ 6-15
• MZ 30-40
• OTHER DISORDERS LESS DIFFERENCE BUT ALWAYS MORE
  MZ THAN DZ

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LIMITS OF TWIN STUDIES

• MZ CONCORDANCE FAR FROM 100
• ARE TWINS REPRESENTATIVE?
• EXTENT GREATER CONCORDANCE FOR MZ IS SOCIAL NOT
  GENETIC
• PHYSICAL SIMILARITY, MORE INTERACTION, SAME
  FRIENDS
• CANT LOCATE PARTICULAR CAUSE

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neurochemistry
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NEURONS
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NEUROCHEMISTRY

• NEURONS (BRAIN CELLS) RELEASE
• NEUROTRANSMITTERS (CHEMICALS THAT COMMUNICATE
  BETWEEN NEURONS) INTO
• SYNAPSES - GAP BETWEEN NEURONS
• RECEPTORS - ABSORB CHEMICALS

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NEUROCHEMISTRY (CONT.)

• MENTAL ILLNESSES CAN ARISE FROM
• MALFUNCTIONING RECEPTORS
• TOO MUCH OR TOO LITTLE OF VARIOUS
  NEUROTRANSMITTERS

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MAJOR NEUROCHEMICALS

• SEROTONIN - LOW LEVELS MAY BE RELATED TO
  DEPRESSION AND MANY OTHER MENTAL ILLNESSES
• DOPAMINE - HIGH LEVELS MAY BE RELATED TO
  SCHIZOPHRENIA
• NOREPINEPHRINE - HIGH LEVELS MAY BE RELATED TO
  ANXIETY

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?s

• ARE NEUROCHEMICAL ABNORMALITIES CAUSES OR EFFECTS
  OF M.I.?
• NO EVIDENCE YET THAT GENETIC/BIOLOGICAL CAUSES
  ARE MORE IMPORTANT THAN OTHERS