Schizophrenia Flashcards
Biological factors: Genetic basis & Candidate genes
Genetic basis: Schiz runs in families Twin studies - Identical = 48% Fraternal = 17%
Candidate genes:
Polygenic + aetiologically heterogeneous
Ripke -
37,000 patients
108 genetic variations that increase risk
Biological explanations: Dopamine Hypothesis
Dopamine is important in the functioning of several brain systems that may be implicated in the symptoms of schizophrenia
Dopamine hypothesis: Hyperdopaminergia
Hyperdopaminergia in the subcortex
Original version
High levels of dopamine in the subcortex
Poverty of speech, auditory hallucinations
Dopamine hypothesis: Hypodopaminergia
Hypodopamingeria in the cortex
Abnormal low levels of dopamine in brains prefrontal cortex
Thinking and decision making
Biological explanations: Neural Correlates
Patterns of structure or activity in the brain that occur in conjunction with an experience
Neural correlates: Negative symptoms
JUCKEL
Found lower levels of activity in ventral striatum and the severity of negative symptoms
Development of avolition
Neural correlates: Positive symptoms
ALLEN
Found the hallucination group had lower activation levels in the superior temporal gurus and anterior cingulate gyrus
Evaluation biological explanation: Genetic basis
Adoption studies show children of schizophrenia sufferers are at a heightened risk even with families with no history of schiz
Available evidence shows genetic susceptibility is important
Evaluation biological explanation: Candidate genes / Dopamine hypothesis
Genes identified by RIPKE play a role for other neurotransmitters
Dopamine may not be the only contributing neurotransmitter
Evaluation biological explanation: Neural Correlates
The brain structure may not be the cause of negative symptoms less info may pass through brain structures causing lower activity
So the existence of neural correlates contribute very little ‘causation’ information
Psychological explanations: Family dysfunction
Schizophrenogenic mother
Schizophrenogenic mother (‘Schizophrenia-causing’)
Based on accounts of patients of their childhood
Cold, rejecting, controlling
Distrust - leads to paranoid delusions
Psychological explanations: Family dysfunction
Double bind theory
Communication style within a family
Dear doing the wrong thing but receive mixed messages
Punished by withdrawal of love -> leads to disorganised thinking/emotions/paranoid delusions
RISK FACTOR NOT A CAUSE
Psychological explanations: Family dysfunction
Expressed emotion
EE to a patient from carer Sources of stress... 1. Verbal criticism 2. Hostility 3. Emotional over involvement
Primarily explanation for replaces or trigger vulnerable people
Psychological explanations: Cognitive explanations
Metarepresentation
Central control
Associated with several types of abnormal information processing
Metarepresentation - cognitive ability to recognise own intentions and actions of others
So disruption to this ability - hallucinations and delusions
Central control - cognitive ability to suppress automatic responses
Disorganised speech and thought disorder as patient cannot suppress this cognitive ability
Evaluation psychological explanations: Family disfunction
READ et al
Reviewed 46 studies of child abuse - 69% women had a diagnosis of schiz and had a history of physical/sexual abuse
Evidence to link family dysfunction
However information was gathered after the development of schiz symptoms, recall of childhood may be distorted
Questions validity of results