Neurobiology of Psychosis Flashcards

1
Q

WHat percent is Schizo heritable?

A

78% heritable

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2
Q

Define heritability.

A
  • the proportion of observable differences in a trait between individuals in a popn (d.t genetic diff.)
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3
Q

Why is childhood hx important with suspected Schizophrenia?

A

2nd trimester illness is a/w with increased risk of Schizo developing by 50%
- Obstetric problems-pre-eclampsia/ fetal hypoxia/ emergency C-section

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4
Q

What drug is least likely to induce psychosis?

A
  • Cannabis

- a.w LATER risk of schizo

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5
Q

How does the coronal section of the brain appear for poor prognosis?

A
  • reduced frontal lobe volume
  • reduced frontal lobe GREY matter
  • enlarged LATERAL ventricle volume
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6
Q

What is neuropril? Where is it predominantly found?

A
  • any area in the NS composed of UNMYELINATED axons, dendrites, and glial cells
  • synaptically dense region with LOW cell bodies
  • —NEOCORTEX and OLFACTORY bulb
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7
Q

Where is GREY MATTER seen to be reduced in a brain of schizophrenic?

A

CONSISTENT reductions seen in temporal cortex and medial temporal lobe

Variable reductions seen in orbitofronal cortex, parietal cortex, basal ganglia

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8
Q

Why is white matter abnormalities considered to also be pathological in schizo?

A
  • normal cognitive functions are partly localized a schizo brain
  • but there is abnormal NEURAL intergration in schizo (white matter is said to CONNECT diff. parts oft the brain)
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9
Q

How to explore the extent of white matter damage?

A
  • DTI (diffuse tensor imaging)
  • –MD-Higher numbers= less healthy WM tracts
  • —FA- higher numbers= more healthier WM tracts
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10
Q

WHat does a higher FA mean in DTI?

A
  • –correlates with psychotic symptom severity

- –d/t myelin abnormalities

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11
Q

What causes the brain pathology in schizo?

A
  • Neuregulin (critical in growth and develop. of multiple ORGAN systems)
  • Dysbudin (essential for adaptive neural plasticity)
  • DISC-1 (invovled in cortical developm.)
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12
Q

How does blocking DOPAMINE cause osteoporosis?

A
  • dopamine is said to have an inhibitory effect on the pituitary release of Prolactin
  • –no dopamine release= HYPERPROLACTINEMIA

> reduce estrogen and testosterone levels >OP

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13
Q

Action on what receptors results in Positive psychotic symptoms?

A
  • 5-HT2A

>hallucinations and thought disturbance

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14
Q

What occurs with antagonism of the H1 receptors centrally?

A
  • central antagonism: SEDATION, loss of APPETITE

- reduces nausea and vomitting

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15
Q

WHat occurs with reduction of Alpha1-Adrenergic activity of blood vessels?

A

Hypotension and interruption of baroreflex response

> dizziness, lightheadedness when rising from a LYING/SITTING position

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16
Q

Blocking dopamine receptors in the pituitary gland brings out what S.Es?

A
  • sexual dysfxn

not acromegaly/sedation/akathesia

17
Q

Antipsychotic acting on what receptors is avoided in pts, at risk of falls (old and frail, already on anti-hypertensives)

A
  • alpha-adrenergic

- histamine blockade

18
Q

What is given for rx of treatment-resistant Schizo?

A
  • Clozapine
19
Q

Huge side effect of Clozapine (Atypical Anti-psychotics)?

A
  • Agranulocytosis
20
Q

How often must one get their FBC checked when on Clozapine?

A
  1. for 6 months: WEEKLY
  2. next 6 months: FORTHNIGHTLY
  3. afterwards: every 4 WEEKS
  4. for ONE month after CESSATION
21
Q

In what special situation is an fbc ordered in when a patient is also on Clozapine?

A
  • when they have any form of Infection

- get FBC (even if it’s a sore throat)

22
Q

What metabolizes clozapine faster?

A
  • not smoking
23
Q

Likelihood of becoming schizophrenic is a first degree relative is schizo?

A

11%

24
Q

What occurs with subcortical dopamine HYPERactivity and MESOCORTICAL dopamine hypoactivity?

A
  • subcortical dopamine hyperact/=> PSYCHOSIS

- Mesocortical dopamine hypoactivity=> negative cognitive symptoms