SCHIZOPHRENIA - Biological Explanations Of Schizophrenia Flashcards
What do family studies teach us about schizophrenia?
Gottesman (1991) = shows that risk of developing schizophrenia increases in line with genetic similarity to a relative with the disorder.
If an aunt has it = there is a 2% chance of developing the disorder
Sibling = 9%
Twin = 48%
What are the role of candidate genes in developing schizophrenia?
- genes that play the role in development of schizophrenia
- schizophrenia is polygenic = development is not determined by a single gene but a few genes.
Ripke et al (2014) = genes associated with increased risk are those which coded for the functioning of he NT dopamine - schizophrenia is aetiologically heterogenous due to different candidate genes being identified
What is the role of mutation in developing schizophrenia?
Mutation in parental DNA which can be caused by radiation , poison and viral infection
Evidence = (Brown et al 2002) = there is a strong correlation between parental age and risk of developing schizophrenia.
What are neural correlates of schizophrenia ?
the physical brain processes that correspond to mental states or events such as schizophrenia.
Dopamine is the best known neural correlate of schizophrenia.
Raise your yayayaya
Yaya
What does the dopamine hypothesis argue ?
Schizophrenia may be a result of high levels of DA in the subcortical areas of the brain
Excess of DA in receptors in pathways from the sub cortex to Broca’s area = explains speech / auditory hallucinations.
Define hyperdopaminergia?
High levels of dopamine
Define hypodopaminergia?
Low levels of dopamine
Explain Davis et al (1991).
Low levels of DA in brains prefrontal cortex which is responsible for thinking explains cognitive problems.
Cortical hypodopaminergia leads to subcortical hyperdopaminergia
Both high and low lvls in diff regions may play a role
Explain Howes et al (2017).
both genetic variations and early experiences of stress, both psychological and physical, make people more sensitive to cortical hypodopaminergia.
Evaluate the genetic basis of schizophrenia.
+ research support = eg Gottesman = risk increases with genetic similarity to a family member with schizophrenia.
eg. Tienari et al (2004) = children of parents w/schizophrenia are at risk even if they grow up in an adoptive family.
eg Hilker et al (2018) = increased concordance rate of 33% for MZ twins and 7% for DZ twins = people are vulnerable to schizophrenia due to their genetic makeup
- environmental factors that are biological and psychological can cause schizophrenia
BIOLOGICAL RISK FACTORS = birth complication + smoking cannabis during teenage years ( MORGAN ET AL)
PSYCHOLOGICAL RISK FACTORS = Childhood trauma leads people to be vulnerable to adult mental health problems.
Morkved et al (2017) - 67% of schizophrenics reported at least one childhood trauma
= genetic factors alone cannot provide a complete explanation for schizophrenia.
Evaluate Neural Correlates of schizophrenia.
+ Research support for the dopamine hypothesis
Curran et al (2004) = Amphetamines increase DA and worsen symptoms in ppl w/schizophrenia and reduce symptoms in people without.
Antipsychotic drugs reduce DA activity + decrease intensity of symptoms (Tauscher et al 2014) =
Some candidate genes act on production of DA or DA receptors = suggests dopamine is involved in symptoms of schizophrenia.
- GLUTAMATE = PMS + live scanning studies found raised levels of NT glutamate in the brains of schizophrenic people. Several candidate genes are involved in glutamate production. = other NT can also cause schizophrenia
