Paper 3 - Schizophrenia Flashcards
What does schizophrenia translate to?
Introduction to schizophrenia
- Means SPLIT MIND
- Nothing to do with a split personality
- SPLIT from REALITY
Introduction to schizophrenia
Perecentages of likelihood of developing schizophrenia
Introduction to schizophrenia
- Identical twins - 48%
- Fraternal twins - 17%
- Parents - 6%
- Grandchildren - 5%
Introduction to schizophrenia
Define Positive Symptoms
Introduction to schizophrenia
Additional experiences beyond those of ordianry existence
Introduction to schizophrenia
Define Negative Symptoms
Introduction to schizophrenia
The loss of usual abilities and experiences
Introduction to schizophrenia
Examples of Positive Symptoms
Introduction to schizophrenia
- Hallucinations
- Delusions
Introduction to schizophrenia
Examples of Negative Symptoms
Introduction to schizophrenia
- Avolition - Lack of motivation to do everyday tasks
- Speech Poverty - Reduced frequency and quality of speech
Introduction to schizophrenia
What is used to diagnose someone with schizophrenia?
Introduction to schizophrenia
- ICD 11 - International Classification of Disease (Negative symptoms)
- DSM 5 - Diagnostic Statistical Manual (Negative + Positive symptoms)
- ICD recognises subtypes e.g. Paranoid, Hebephrenic, Catatonic
- NHS uses ICD 11
Introduction to schizophrenia
Hebephrenic Schizophrenia
Introduction to schizophrenia
- Disorganised behviour without purpose
- Disorganised thoughts - others may find difficult to understand you
- Usually develops between 15-25
Introduction to schizophrenia
Paranoid Schizophrenia
Introduction to schizophrenia
- Most common
- Prominent hallucinations/delusions
- May develop at later age than other types
- Speech + emotions may be unaffected
Introduction to schizophrenia
Catatonic Schizophrenia
Introduction to schizophrenia
- More rare
- Unsusual movements, often switch between over-actvitity and stillness
- May not talk at all
Introduction to schizophrenia
Define external reliability
Diagnosing Schizophrenia
Consistency of results from a test when done again
Diagnosing Schizophrenia
Define Inter-Rater Reliability
Diagnosing Schizophrenia
Consistency of ratings by different people
Diagnosing Schizophrenia
External Reliability - Schizophrenia
Diagnosing Schizophrenia
Consistency of diagnosis of the same patient (over time) given no chnages in symptoms
Diagnosing Schizophrenia
Inter-Rater Reliability - Schizophrenia
Diagnosing Schizophrenia
Consistency of diagnosisof the same patient given by different psychiatrists
Diagnosing Schizophrenia
Problems with reliability of diagnosis - Cheniaux et al (2009)
Diagnosing Schizophrenia
- Method - 2 psychiatrists independently diagnosed 100 patients using DSM 4 and ICD 10 criteria
- Results - Schizophrenics diagnosed by psychiatrist 1 = DSM - 13 and ICD - 24
Different = Poor external validity - Psychiatrist 2 = DSM - 26 and ICD - 44
- DSM - poor inter-rater reliability
Diagnosing Schizophrenia
Jakobsen et al (2005)
Diagnosing Schizophrenia
- 100 Danish patients with history os psychosis - assessed using both manuals + found a near perfect agreement (kappa = 0.87)
- High external rleiability of clinical diagnosis of schizophrenia
Diagnosing Schizophrenia
Validity of schizophrenia
Diagnosing Schizophrenia
Extent to which schizophrenia is actuallly a syndrome with specific characteristics signs and symptoms.
Diagnosing Schizophrenia
Validity of diagnosis
Diagnosing Schizophrenia
Are we correctly diagnosing people who have the disorder?
Diagnosing Schizophrenia
How well a diagnosis applies to different:
Diagnosing Schizophrenia
- People (Cultural/Population)
- Places (Ecological)
- Times (Historic/Temporal)
Diagnosing Schizophrenia
PEEL Paragraph - Problems with external reliability of diagnosis
Diagnosing Schizophrenia
P - Overlapping symptoms with other disorders
E - Contrasting symptoms with depression. E.g. Flat affect and lack of hygiene are also symptoms of depression aswell as schizophrenia
E - Sometimes patients can be diagnosed as schizophrenic using one classfication system
L - This calls into question whether SZ is being reliability diagnoses as it presents similarly to other disorders
Diagnosing Schizophrenia
PEEL Paragraph - Problems with internal vailidity of diagnosis
Diagnosing Schizophrenia
P - Disorder is often comorbid
E - Comorbidity means more than one illness /disease occuring in one person at the same time
E - Buckley et al 2009 - studied patients with diagnosed SZ. Looked at comorbidity rates with other disorders:
50% - Depression
47% - Substance abuse
29% - PTSD
23% - OCD
L - Reduces validity because psychiatrists cannot tell which symptoms are attributed to which disorder
Diagnosing Schizophrenia
Candidate gene
Biological Causes
Gene whose chromosomal locatiom is associated with a particular disease/other phenotype
Biological Causes
Dopamine
Biological Causes
Neurotransmitter which plays a role in how we feel pressure
Biological Causes
Aetiologically Heterogenous
Biological Causes
Number of different combinations of genes can lead to illness
Biological Causes
Polygenic
Biological Causes
Phenotype is influenced by more than one gene
Biological Causes
How is schizophrenia a polygenic disorder?
Biological Causes
Ripke et al - 108 genes
Biological Causes
Evaluation - Adoption Studies
Biological Causes
Impact on nurture on children who are raised by parents who are not their biological parents
Biological Causes
How can they show if schizophrenia has a genetic basis?
Biological Causes
No biological connection between the parent and the child, if child grows up to share parent’s traits, probably produced by nurture
Biological Causes
Schizophrenic’s Prefrontal cortex
Biological Causes
Lower activity - delusions + disorganised thoughts
Biological Causes
Schizophrenic’s Visual + Auditory cortex
Biological Causes
Same activity - when they halluicante as sane peopple do when they have genuine visual and auditory experiences
Biological Causes
Schizophrenic’s Basal ganglia
Biological Causes
Larger - cause more motor dysfunction
Biological Causes
Schizophrenic’s Amygdala
Biological Causes
Smaller - link to loss of emotion (affective flattening)
Biological Causes
Schizophrenic’s Dopamine
Biological Causes
Low levels in certain brain areas - negative symptoms - loss of pleasure.
HIgh levels - positive symptoms
Biological Causes
Superior Temporal Gyrus
Biological Causes
Associated with attributing stimuli to internal + external causes
SZ - lower levels lead to hallucinationsand feelings they are not in control of their own body
Biological Causes
Ventral Striatum
Biological Causes
Involved in anticipation of reward
SZ - low levels result in loss of motivation (apathy and avolition)
Biological Causes
Synaptic Transmission
Dopamine Hypothesis
- Never impulese travels down Axon in presynaptic neuron
- Reaches axon terminal of presynaptic neuron
- Triggers release of neurotransmitter from it’s vesicle into synaptic gap
- Neurotransmitters diffuses across synaptic gap
- NM bind to receptor sites on postsynaptic neuron
- Triggers a new impulse in the next neuron - process begins again
- NM travel back to presynaptic neuron and is repachaged into it’s vesicle (reuptake)
Dopamine Hypothesis
What is an amphetamine?
Dopamine Hypothesis
Increases dopamine - produces symptoms which are similar to SZ symptoms e.g. hallucinations + delusions
Dopamine Hypothesis
Study which led to the development of the hypothesis - Randrup et al (1966)
Dopamine Hypothesis
Behaviour similar to that found with SZ was induced rats of amphetamine + the effect was reversed with anti-psychotic drugs
Dopamine Hypothesis
Study which led to the development of the hypothesis - Iverson (1979)
Dopamine Hypothesis
Obtained results below from research into dopamine receptors using post-mortem examinations
Dopamine Hypothesis
