Schizophrenia guided notes Flashcards
Describe the main features of schizophrenia
At least 2 of the five key symptoms must be present for a one month period or longer
a: delusions
b: hullucinations
c: disorganised speech
d: disorganised or catatonic behaviour
e) negative symptoms
Differentiate between positive and negative symptoms
Positive vs. Negative symptom dimensions:
– Positive symptoms
* reflect an excess of behaviour not usually seen or the presence of an abnormal mental process
(delusions, hallucinations, disorganised speech or behaviour [formal thought disorder])
* most prominent during acute phase of illness
– Negative symptoms
* reflect diminution / absence of a mental function that is normally present (apathy, flat affect,
social withdrawal, lack of spontaneous movement)
* tend to be chronic
Positive vs. Negative symptom dimensions:
– Positive symptoms
* reflect an excess of behaviour not usually seen or the presence of an abnormal mental process
(delusions, hallucinations, disorganised speech or behaviour [formal thought disorder])
* most prominent during acute phase of illness
– Negative symptoms
* reflect diminution / absence of a mental function that is normally present (apathy, flat affect,
social withdrawal, lack of spontaneous movement)
* tend to be chronic
List the main factors suggested to interact in the aetiology of schizophrenia
The aetiology (cause) of schizophrenia is unclear; but is based on an interaction of:
* Biological factors: ‐ genetics
‐ abnormalities of brain structure and function
‐ neurotransmitter abnormalities (chemicals in the brain)
* Psychosocial factors (environment
Explain the neurodevelopmental hypothesis
a disruption of brain development during early life underlies the later emergence of psychosis during adulthood
(potentially with a “second‐hit” in adolescence)
* Different brain functions come “on‐line” at different stages during development. Functional consequences of brain
changes in schizophrenia may be developmentally moderated so that the later in life a function comes on‐line, the
more likely it is to be disordered
* Has evolved to become the Developmental Risk Factor Model
Explain the dopamine hypothesis
schizophrenia is caused by too much dopamine however then found high lvels of activity at dopamine receptors. and anti psychotic drugs exert their effect by decreasing dopamine levels
found reserpine to deplete dopamine, chlorpromazine does not
Explain genetic factors and epigenetic mechanisms in relation to schizophrenia
Twin, adoption, and family studies indicate a large hereditary component (~80%):
– Twin studies: See reviews by Slater (1968), Gottesman (1991): MZ twins > DZ twins
for schizophrenia concordance; lack of 100% MZ concordance indicates non‐
mendelian inheritance (and contribution of environmental risk)
– Adoption studies: Rates are higher in children of patients than control adoptees
(e.g., Tienari et al., 2000: 6.7% in Sz‐offspring adopted away vs. 2% controls)
– Family studies: Risk of schizophrenia increases in proportion to familial proximity
and number of affected relatives
Epigenetic mechanisms may mediate gene‐environment interactions
* Three groups of mechanisms examined:
1. DNA methylation – blocks the binding of transcription factors at gene promoters and alters chromatin
structure and thereby regulates gene expression and gene silencing
2. Histone modifications – modifications to the proteins that package and order DNA into nucleosomes;
may be transcriptionally permissive or repressive
3. Non‐coding microRNAs (miRNAs) – single‐stranded non‐coding RNAs that function in RNA silencing and
post‐transcriptional regulation of gene expression
* Evidence for epigenetic modulations of genes that regulate neurotransmission (dopamine, serotonin, GABA,
and neurotrophin), neurodevelopment, and immune function, as well as differential levels of miRNA
expression (e.g., miR‐137 influences synaptogenesis and pre‐synaptic micro‐structure and function ‐>
reduces synapse density and performance)
* Important to understanding variation in phenotypic expression (Sx heterogeneity) and medication response.
Outline the major cognitive deficits associated with schizophrenia
- episodic memory
- workign memory
- executive control
-
Describe the main brain abnormalities associated with schizophrenia
‐ siginficantly larger lateral ventricles
- limbic system reduced (amygdala, hippocampus)
- grey and white matter volume decrease
features of schizophrenia
- 2 percent of the general population
- mean age of onset: males = 26.5, females 30.6
- onset is either acute or emerges gradually from a prodromal phase (this is the begining phase where symptoms are more low key)
- 83 percent acheive partial remission during firsit year of treatment, 82 percent experiencex at least one relapse within 5 years
neuropathology
- quantitative and qualitative deficits in nueral process and synaptic connectivity
