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Flashcards in Psychotic Disorders Deck (17)
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1

Diagnostic criteria for schizophrenia

  • Characteristics symptoms (2 for at least one month):
    • delusions
    • hallucinations
    • disorganized speech
    • grossly disorganized or catotonic behavior
    • negative symptoms such as affective flattening
  • social/occupational dysfxn
  • duration of symptoms for at least 6 months
  • mood disorder isn't major part of illness
  • illness not due to medication/medical condition or substance abuse
  • illness is not part of autism/developmental disorder

2

Characteristics of Psychotic patients

  • primary disorder in thinking
  1. hallucinations = hear voices, experience other unreal sensations
  2. paranoid delusions = influenced by unseen forces around them
  3. persecutory delusions = tormented, harmed, followed, tricked or spied on
  4. formal thought disorder = idiosyncratic association; disorganized speech or writing

3

Characteristiscs of schizophrenia

  • chronic, debilitating psychotic psychiatric disorder
  • impacts 1% of people worldwide
  • sx often begin in late adolescense or early adulthood
  • positive sx: psychosis (delusions, hallucinations)
  • negative sx: inability to pay attention, disorganized thoughts/speech, flattened affect, social withdrawal

4

Genetic causes of schizophrenia

  • heritable component established by epidemiology, twin studies, and adopted children from schizophrenic mothers
  • polygenic disorder = several small genes associated w/increased risk
  1. rare copy number variants of strong effect: on chromosomes 1q, 2p, 15q, 16p, 22q
    1. genes involved in neuronal development
  2. Large scale genome wide association studies: small nucleuotide polymorphisms
  3. linkage and candidate gene: key growth factors and regulators of neurodevelopment
  4. family-based exome sequencing: higher incidence of de novo mutations 

5

Environmental causes of schizophrenia

  • viruses
  • malnutrition before birth
  • birth complications
  • other psychosocial factors

6

Neurotransmiter theories of schizophrenia

  • dopamine
  • glutamate
  • GABA

7

Dopamine theory of schizophrenia

  • disregulation of dopamine ==> psychosis
  • mesolimbic system = VTA ==> nucleus accumbens
    • hyperactivity ==> positive sx of schizophrenia
  • mesocortical system = dopamine neurons @ VTA (==>prefrontal cortex) & substantia nigra (==>basal ganglia)
    • hypoactivity ==> negative sx of schizophrenia

8

Glutamate model of schizophrenia

  • Glutamate can bind to dopaminergic neurons ==> regional hyperactivity and hypoactivity of dopamine release
  • chronic NMDA antagonist administration ==> persistant elevation of DA release @ nucleus accumbens + decreased DA release @ prefrontal cortex

9

Neural circuitry hypotheses of schizophrenia

  • association cortex
  • medial temporal lobe and hippocampus
  • thalamus
  • basal ganglia

10

Association cortex role in schizophrenia

  • association cortex = brain outside of primary sensory cortices
    • includes dorsal lateral prefrontal cortex (DLPFC) = executive fxn
  • volume reduction of association cortex has been seen in schizophrenia
  • cerebral blood flow and glucose metabolism are abnormal @ rest and during cognitive tasks
  • hypofrontality observed in neuroimaging during working memory
  • hyperactivity of DLPFC during task performance = indicator of prefrontal inefficiency

11

Medial temporal lobe and hippocampus role in schizophrenia

  • mild cortical atrophy @ medial temporal lobe
  • abnormal alignment of neurons @ medial temporal lobe structures
  • hippocampal dysfxn ==> dysfxn w/in its circuits (memory, emotion)
    • altered synaptic organization
    • fewer nonpyramidal cells
    • inreased metabolism/blood flow @ baseline
    • associated w/positive sx

12

Role of thalamus in schizophrenia

  • thalamus = gateway for all incoming sensory info
  • proposals:
    1. decreased thalamic volume ==> decreased sensory-gating ==> increased stimulation at primary sensory cortices
    2. dysfxn @ dorsal medial nucleus ==> impairments of cortical association areas

13

Role of basal ganglia in schizophrenia

  • possible changes in volume of caudate nucleus/other basal ganglia nuclei

14

First generation antipsychotics

  • phenothizines
  • thioxanthines
  • butyrophenones

15

First gen. antipsychotics: MOA & SE

  • MOA: target dopamine D2 receptor
  • SE:
    • parkinsonianism 
    • tardive dyskinesia = choreoathetosis

16

Second generation antipsychotics

  • also called "atypical neuroleptics"
  • Clozapine
  • risperidone
  • olanzapine
  • quetiapine
  • asenapine
  • ziprasidone

17

Second generation antipsychotics: MOA & SE

  • ==> antipsychotic effects w/parkinsonian SEs
  • MOA: blocks several receptor types (ACH, serotonin, NE, dopamine) but w/weaker dopaminergic action
  • SE: enhanched appetite ==>
    • weight gain
    • hypercholesterolemia
    • diabetes