BIOLOGICAL%20THEORIES

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BIOLOGICAL THEORIES
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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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TREATMENT
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• BEFORE LOBOTOMY, SHOCK, COMA - NOW DRUGS
• CHANGE NEUROCHEMISTRY OF BRAIN
• ELEVATE OR LOWER LEVELS OF NEUROTRANSMITTERS IN
  SYNAPSES AND WHAT RECEPTORS ABSORB

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TREATMENTS

• ANTI-PSYCHOTICS
• LITHIUM FOR BIPOLAR
• PHENOTHIAZINES AND CLOZAPINE FOR SCHIZOPHRENIA
• ILLNESS SPECIFIC

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SSRIS

• SELECTIVE SEROTONIN REUPTAKE INHIBITORS - PROZAC,
  PAXIL, XOLOFT (LATE 1980S)
• UNLIKE OLDER DRUGS ARE SPECIFICALLY DESIGNED TO
  PREVENT REUPTAKE OF SEROTONIN
• NOT ILLNESS SPECIFIC (NOT ANTI-DEPRESSANTS)

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HUGH GROWTH
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ARE SSRIS BETTER?

• NOT MORE EFFECTIVE THAN OLDER DRUGS
• FEWER NEGATIVE SIDE EFFECTS (ALTHOUGH POSSIBLY
  MORE SUICIDE RISK)
• NOT ADDICTING

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DOWNSIDE OF SSRIS

• MAY NOT BE MUCH BETTER THAN PLACEBOS
• LONG-TERM EFFECTS?
• ONLY ELIMINATE SYMPTOMS, NOT UNDERLYING PROBLEM?
• BENEFITS OVERSTATED

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STRENGTHS AND LIMITS
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STRENGTHS OF BIOLOGY

• BEST FOR PSYCHOTIC DISORDERS
• MORE KNOWLEDGE ABOUT BRAIN
• ADVANCES IN DRUG TREATMENTS FOR MANY CONDITIONS

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LIMITATIONS
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1. OVERSTATEMENTS

• MOST CONVINCING FOR PSYCHOSES
• LESS EVIDENCE FOR OTHERS
• ARE CHEMICAL IMBALANCES CAUSES OR EFFECTS?

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2. GENES NOT DESTINY

• ONLY A MINORITY OF PEOPLE WITH GENETIC
  SUSCEPTIBILITY DEVELOP DISORDER
• OFTEN NEED ENVIRONMENTAL PRECIPITANT
• ENVIRONMENT CAN SUPPRESS - MORMONS AND ALCOHOLISM

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3. WHAT DOES A GENE DO?

• DIFFERENCE OF GENOTYPE AND PHENOTYPE (APPEARANCE)
• E.G. ANOREXIA
• CULTURE CAN SHAPE PHENOTYPE
• GENES MAY HAVE GENERAL, NOT SPECIFIC, EFFECTS

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4. MOST M.I. NOT GENETIC

• MOST PEOPLE WHO GET A DISORDER DO NOT HAVE
  GENETIC PROPENSITY TO THE DISORDER

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SCHIZ. IN DENMARK

• THOSE WITH 1ST DEGREE RELATIVES HAVE 10x RATE OF
  SCHIZ
• BUT 90 OF PEOPLE WHO DO GET SCHIZ HAVE NO SCHIZ
  RELATIVES
• FAR MORE PEOPLE HAVE NO FAMILY HISTORY OF SCHIZ
  SO DESPITE LOWER PRODUCE MORE CASES