Summary
Summary Schizophrenia Notes
- Module
- Schizophrenia
- Institution
- AQA
AQA Psychology Paper 3 - notes on Schizophrenia topic including AO1 and AO3
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Diagnosis and Classification of SchizophreniaAO1 - knowledge AO3 - evaluation
Schizophrenia is a serious mental disorder experienced by about 1% of the world Strength - Good reliability
Flávia Osório et al. (2019) reported excellent reliability of DSM-5 diagnosis in 180 patients. Pairs of
population. Those with schizophrenia often experience a ‘split mind’ between interviewers had inter-rater reliability of +97 and test-retest reliability of +92. This means that diagnosis of
what is real and what is not, a form of psychosis. schizophrenia is consistently applied and thus patients are accurately diagnosed.
ICD-10 and DSM-5
Created by WHO, the ICD-10 states that two or more negative symptoms must be Weakness - Low validity
present to diagnose individuals. The ICD-10 was created by the American Diagnosis of schizophrenia is inaccurate and can be shown through criterion validity. Elie Cheniaux et al.
(2009) had 2 psychiatrists assess patients under DSM-5 and ICD-10 respectively and found that 68 were
Psychiatric Association and states that diagnosis is based on one or more diagnosed with schizophrenia under the ICD-10 and 39 under the DSM-5. This means that patients are either
positive symptom. Previous editions of both systems identified subtypes but this over or under diagnosed, depending on which diagnostic system is used.
has since been removed due to inconsistency.
Positive symptoms - excess of normal functioning Weakness - Co-morbidity
Hallucinations One review found that about half of those with schizophrenia also suffered from depression or substance
abuse. Buckley et al. found that 50% of those with schizophrenia also have depression, 47% suffer from
These are unusual sensory experiences. They can be auditory (hearing voices), substance abuse and 23% have OCD as well. This could suggest that schizophrenia is not a distinct
visual (seeing things), olfactory (smelling a non-existent fire) or tactile (feeling condition but just extreme cases of other conditions.
bugs crawling over you).
Delusions
These are irrational beliefs. Common delusions involve being an important
Weakness - Gender bias
historical figure, like Jesus or Napoleon. Others include being persecuted by the Fisher and Buchanan (2017) found that men and women are diagnosed at a ratio of 1.4:1. This could be
government perhaps. due to genetic factors but Cotton et al (2009) suggests that it is actually because women are more inclined
to form closer relationships and so have more social support to help them function. This means that women
are unable to access treatment and services that will benefit them.
Negative symptoms - lack of normal functioning
Speech poverty
When the individual loses the quantity and quality of speech i.e slow verbal
Weakness - Culture bias
responses. In Haiti, hearing voices is seen as communication with one’s ancestors. Pinto and Jones (2008) found that
Avolition Black-British people are 9x more likely to be diagnosed with schizophrenia in comparison to white British
This refers to a lack of motivation e.g lack of hygiene, energy, persistence. people. This is because diagnosis is carried out by someone from a different culture. Escobar (2012)
believes this leads to an overinterpretation of symptoms on black people.
, Biological Explanations for Schizophrenia
AO1 - knowledge AO3 - evaluation
Strength - Research support
The genetic basis Pekka Tienan et al. (2004) show that biological children of parents with schizophrenia have an increased
Family studies vulnerability to the disorder even if they grow up in an adoptive family. This clearly shows how some people
Family studies confirm an increased vulnerability to schizophrenia with genetic are more vulnerable due to genetics over any psychological or environmental factor.
similarity. Gottesman (1991) found that if an individual has an aunt with
schizophrenia they have a 2% chance of developing it, increasing to 9% for a Weakness - Environmental factors
sibling and 48% for an identical twin. These percentages do include The genetic explanation is limited. Biological risk factors include birth complications (Morgan et al. 2017) and
smoking THC-rich cannabis in teenage years (Di Forti et al. 2015). Psychological factors include childhood
environmental similarities. trauma. Nina Mørkved et al. (2017) carried out a study in which she found that 67% of schizophrenic people
Candidate genes reported childhood trauma in comparison to 38% of a control group.
Schizophrenia is polygenic. Ripke et al. (2014) combined all previous data from
genome-wide studies of schizophrenia and compared to controls. 108 separate Genetic counselling
variations were associated with a slightly increased risk of schizophrenia. This One application of the genetic explanation is genetic counselling. If one or more parents have a relative with
schizophrenia, they risk having a child who would go on to develop the condition.
also means that schizophrenia is aetiologically heterogeneous. However, the risk estimate is just an average figure as it doesn’t take into account environmental risk factors.
Mutation
Schizophrenia can be traced back to mutation in parental DNA due to radiation,
poison or viral infection. Brown et al (2002) found a correlation between paternal Strength - Evidence for dopamine
First, amphetamines increase dopamine levels. Curran et al. (2004) found that using amphetamines can
age (increased risk of sperm mutation) and schizophrenia. worsen schizophrenia symptoms or even induce symptoms. Second, antipsychotics reduce dopamine levels.
Tauscher et al. (2014) found that antipsychotics lessen schizophrenia symptoms. Third, some candidate
genes are linked with dopamine production. This provides strong evidence for the involvement of dopamine
Neural correlates in schizophrenia.
The original dopamine hypothesis
Schizophrenia may be the result of hyperdopaminergia, high levels of dopamine Weakness - Glutamate
in the subcortical areas of the brain. For example, an excess of dopamine in the Post-mortem and live scanning studies have consistently found raised levels of the neurotransmitter
pathways between the subcortex and Broca’s area explains speech avolition. glutamate in several brain regions of those with schizophrenia. Some candidate genes can also be linked to
Updated versions glutamate production. There is an equally strong evidence base for other neurotransmitters.
Davis et al (1991) proposed the addition of low dopamine in the brain’s cortex i.e
both hyper- and hypodopaminergia. Howes et al. (2017) also suggests that Amphetamine psychosis
Tenn et al. (2003) induced schizophrenia symptoms in rats using amphetamines and then relieved these
genetic variations as well as early experiences of stress, both psychological and symptoms using drugs that reduce dopamine action. However, other drugs that also increase dopamine
physical, can cause this imbalance. levels, like apomorphines do not cause schizophrenia symptoms.
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