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Schizophrenia: pos. symptoms
- presence or exaggeration of behaviors
- ->delusions, hallucinations, thought disorder, bizarre behavior
- often acute
- respond to anti-psychotic medications
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Schizophrenia: neg. symptoms
- absence of normal behaviors
- ->lack of emotion
- ->inability to experience pleasure
- ->lack of motivation
- ->poverty of speech
- ->impaired attention
- tend to be chronic
- patients typically have:
- ->poorer adjustment to prior onset
- ->poorer prognosis is after diagnosis
- ->tissue defect, intellectual and cognitive deficits
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onset of Schizophrenia in men vs. women
- equal onset
- ->men in teen/20's
- ->women a decade later
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heredity of Schizophrenia
- higher prevalence among relative with Schizophrenia
- identical twins are 3x more likely to get Schizophrenia as fraternal twins
- ->estimated between 0.60 and 0.90
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vulnerability model
- genes only determine a vulnerability for Schizophrenia
- ->threshold of causes forces must be exceeded
- ->environmental challenges combine with genetic vulnerability
- environmental influences work in park by epigenetic means, up-regulating and down-regulating gene functioning
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vulnerability model figure
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neurotransmitters that serve roles schizophrenia
- excess dopamine causes this disease->blocking dopamine receptors, useful treatment
- amphetamine=similar effects
- some schizophrenic's are deficient in dopamine
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glutamate theory
- due to reduced glutamate activity
- PCP blocks NMDA glutamate (resembles schizo)
- glycine activates the NMDA receptor
- ->improves negative and cognitive systems
- atypical anti-psychotic decrease reuptake
- dopamine imbalance may be result of reduced glutamate activity in PFC
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hypofrontality (brain anomaly)
- decline in frontal lobe function
- wisconsin card sorting test requires reversing strategies
- ->schizo. perform poorly on this task
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winter birth effect
- -environmental cause
- ->more schizo. born in winter
- 2nd trimester in fall/early winter; high incidence of infectious diseaseschizo. births doubled following the 1944-1945 food blockade of the Netherlands
- ->supported by study in china
- risk for schizo. increase by 2/3 if father is older than 50 at conception
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affective disorders
- serotonin, when imbalanced within the brain, lead to and influence the mood and onset of depression when one/two copies of the "short" allele of the 5-HTTLPR serotonin transporter gene are in someones brain, that person has an increased vulnerability
- ->15% reduction in gray matter in amygdala
- ->25% reduction in the subgenual anterior cingulate cortex
- increase in stress
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bipolar heritability
- 85% and 93%
- 69 genes identified
- many genes overlap with those in substance abuse
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monoamine hypothesis
- depression involves reduced activity at Ne and 5-H+ synapses
- effective antidepressant drugs increase activity of one or both transmitters
- -monoamine oxidase (MAO) inhibitors
- -trycyclic antidepressants
- -atypical or 2nd generation antidepressants
synaptic effects take hours; improvement takes weeks
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monoamine oxidase (MAO) inhibitors
block the destruction of excess monoamine's in the terminals
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tricyclic antidepressants
block reuptake at the synapse
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atypical OR 2nd generation antidepressants
- affect a single transmitter
- ex: prozac is a single selective serotonin reuptake inhibitor
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electroconvulsive therapy (ECT)
- 70 to 130 volts to head = convulsive seizure
- therapeutic effects rapid
- reserved for special cases
- increase in sensitivity of serotonin receptors
- sensistivity of pre-synaptic autorecptors is reduced
- ->increased norepinephrine and dopamine relseased
- brain excitability decreases due to an increase in GABA
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anxiety
- involved deficits in GABA and serotonin
- ->treated with antidepressants that modulate serotonin
- brain areas involved:
- ->amygdala
- ->locus coeruleus
- ->parahippocampal gyrus (panic)
- ->regions of the PFC
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PTSD: post traumatic stress disorder
- recurring thoughts and images, nightmares, overreacting to stimuli triggered by combat and sexual assault
- vulnerability factors
- ->smaller hippocampus
- ->heritable about 30%
- treatment
- ->exposure therapy; extinction process
- ->fear erasure and virtual reality
- females are 4x more likely to develop
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