Download What are affective disorders?

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Disorders of mood
◦ found throughout history
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unipolar or major depression
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bipolar or manic depression
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Depression
◦ over 10% with ~ 5% (11,000,000) suffering from a
depressive episode in any given year
◦ untreated - 25 - 30% will attempt or commit suicide
◦ 2X greater prevalence in women than men
◦ estimated only ~ 50% receive specific treatment
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Genetics
◦ concordance rates:
 fraternal twins - 20% concordance
 monozygotic or identical twins - 50% concordance
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Neurochemical Theory
◦ monoamine theory:
◦ supportive data
1. Reserpine
2. Drugs used to treat depression increase activity of
NE and/or 5HT neurons
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Pharmacologically
◦ drugs have been available for ~ 40+ years
◦ two categories of drugs emerged about the
same time; tricyclic antidepressants and MAO
inhibitors
◦ more recently SSRIs have taken over the market
◦ Even more recently SNRI (ex. Effexor® or
venlafaxine)
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Blocks reuptake of NE and 5HT
very widely used
fairly significant side effects
◦ effects on other NT
◦ sedation, weight gain
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mechanism of action: block the enzyme that
breaks down excess NE and 5HT
proved as effective (if not more so) than
traditional tricyclics or SSRIs
not used as first level txt due to risk of
adverse side effects- related to diet
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Alters the metabolism of amino acid
tyramine
◦ foods high in tyramine include: aged cheeses,
wine, smoked fish, yeast products
◦ consumption of these can result in a
hypertensive crisis:
 severe headaches, heart palpitations. Flushing,
nausea, vomiting, stroke
◦ very long 1/2 life (2 weeks)
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Fluoxetine (Prozac) - first introduced in US in
1988
SSRIs have a more favorable side effect profile
than earlier antidepressants
relatively safe (esp in OD situations)
some controversy…... – increased risk of
suicide – especially in kids
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SNRI – serotonin and norepinephrine reuptake
inhibitors
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Some patients do not respond well to first
treatment
most take 3 - 4 weeks to exert significant
therapeutic effects
◦ what does this suggest?
1. ECT - electroconvulsive therapy
◦ may cause the most rapid change in receptor
density
2. Sleep deprivation
◦ many sleep abnormalities associated with
endogenous depression
 reduced SWS, increased stage 1, increased REM
3. Phototherapy - Seasonal Affective Disorder
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Shifts between manic and depressive states
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Treatment:
◦ Lithium – extremely toxic!
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introduced in 1990’s to treat bipolar
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possible mechanism?