Schizophrenia and ASD Flashcards
Is schizophrenia a heterogenous- or homogenous disorder?
Heterogenous disorder
What are the four stages of schizophrenia?
- Premorbid
- Prodrome
- Onset/ Progression
- Residual
In order for schizophrenia to be diagnosed, 2 out of 5 symptoms must be present. Name them!
Speech disorganised, disorganised behaviour, hallucination, negative symptoms, delusions
Why are we referring to schizophrenia as a “neurodevelopmental disorder”?
The interaction between multiple genes trigger a cascade of multiple neurologicalpathological events
When is the abnormal developmental trajectory of the disease established?
During gestation, long before the onset of symptoms.
How do we call the frequently observed enlargement of the ventricles?
Ventriculomegaly
What happens to grey matter in many cases of schizophrenia?
Severe loss of grey matter.
What is observed in many brain regions in schizophrenia patients?
Reduction in size.
Why are brain connections in schizophrenia patients reduced?
Over pruning of synapses.
What are the two theories used to explain the symptomology of schizophrenia?
- Dopamine hypothesis
- Excitory-Inhibitory Balance hypothesis
Where is dopamine being produced?
Basal ganglia & ventral tegmental
Name the three important dopamine projections/ pathways!
- Nigostratral dopamine pathway
- Mesolimbic dopamine pathway
- Mesocortical dopamine pathway
Describe the mechanisms that act according to the dopamine hypothesis!
Hyperactive dopamine transmission in the mesolimbic areas causes overactivity of the mesolimbic pathway which is associated with the positive symptoms.
Hypoactive dopamine transmission in the mesocortic area causes dysfunction of the mesocortiyal pathway and is associated with negative and cognitive symptoms.
Describe the mechanisms that act according to the Excitatory-Inhibitory hypothesis
Excitatory signals acting on “Glutamatergic excitatory neurons” and inhibitory signals acting on “GABAergic inhibitory neurons” are out of balance.
Usual oscillations are not occurring.
Also inhibitory interneurons are thought to be involved.
In order for ASD to be diagnosed, a child must have clinically significant, persistent and since early childhood present symptoms in two categories. Which are they?
- Deficient social communication and interaction
- Restricted repetitive patterns of behaviour, interests and activities.
ASD is involved in multiple altered developmental processes. Which are they in the first & second- and during the third trimester?
- First & second trimester:
- Disruption of proliferation, neurogenesis, migration, outgrowth & laminar organisation. - Third trimester & postnatal:
- Alterations in spine formation, synaptogenesis, synapse function
What is the largest risk factor for ASD?
Genetics
What was shown by GWAS studies regarding the gene expression of genes thought to be involved in ASD?
Strong expression during prenatal development but not during postnatal (cortex) development.
How could a maternal infection increase the risk for ASD?
Maternal cytokines & anti-brain autoantibodies may enter the placenta and alter fetal development.
What is the larger environmental risk factor for ASD?
Cerebella injury at birth.
What are brain structure changes that are frequently observed in cases of ASD?
More CSF
Larger brain volume
Altered brain connection
E-I imbalance
Altered long-range- and short-range connection
What does the abnormal regulation in brain growth in ASD cases result in?
Abnormal accelerated growth is followed by abnormally slowed growth
What happens to the amygdala in many cases of ASD?
It is initially larger but does not undergo typical enlargement in other children.
Ends up with smaller and densely packed cells.
