Schizophrenia Flashcards
What are the two classification systems used for diagnosing schizophrenia
DSM-5 requires one positive symptom to be present for 6 months
ICD-11 requires 2 or more negative symptoms to be present for 6 months
What are the positive symptoms of schizophrenia
These are symptoms in addition to normal functioning and include delusions and hallucinations
What are hallucinations
They are unusual perceptions of reality that are unique to the sufferer and others can not perceive. Hallucinations can affect all senses but are usually visual or auditory. They can be tactile (touch) and olfactory (smell)
What are delusions
They are irrational beliefs that seem real to the sufferer but are not in reality. There are two types of delusions, paranoid and delusions of grandeur.
Paranoid delusions; (worries) the individual often believes they are being persecuted by others for example they may believe that they are being followed
Delusions of Grandeur; exaggerated beliefs of ones own abilities or abilities, often thinking that they are better/above others for example they may believe that they are famous
What are the negative symptoms of schizophrenia
These are symptoms that involve a reduction in normal functioning, these symptoms often appear before the positive ones. They include speech poverty and avolition.
What is speech poverty
A significant reduction in the volume or quality of speech, it can include reduced verbal fluency, reduced language complexity or a notable delay in verbal response during conversation. ‘Word salad’ words often come out unintentionally disorganised
What is avolition
A difficulty to begin and maintain goal-directed behaviour, can involve significantly reduced self motivation to partake in certain things despite having the opportunity and ability to. Presented as a low/flat mood with no motivation to do things.
How is reliably in the diagnosis of schizophrenia assessed
Refers to the consistency of measuring symptoms, assessed by;
1.Test-restest reliability - refers to the extent to which the same clinician makes the same diagnosis on different occasions provided with the same information
2.Inter-rater reliabilty- the extent to which different clinicians make identical,independent diagnoses
How is the validity in the diagnosis of schizophrenia assessed
Refers to the accuracy of measuring symptoms and whether the classification systems can distinguish schizophrenia from other disorders
1. concurrent validity: a diagnosis has concurrent validity if the different systems arrive at the same conclusion using there own criteria to identify symptoms
2. predictive validity refers to the extent to which diagnosis leads to successful treatment which helps to reduce symptoms
How does cultural bias create an issue within the reliability of diagnosis
Cultural bias concerns the tendency to over- diagnose members of ethnic minorities. The people who create diagnostic tools such as DSM are from predominantly white backgrounds and western cultures with a different set of norms and values to other ethnic groups.
This can effect reliability as an individual reporting the same symptoms to clinicians from different cultural backgrounds may not receive the same diagnosis for example people from afro-carribean descent are several times more likely to be diagnosed than white people.
Describe some evidence for cultural bias effecting reliability
Lurhmann: interviewed 60 adults diagnosed with schizophrenia (20 from Ghana,India and US) about the voices they heard
-ghanians and Indians both reported positive experiences compared to no Americans
-implies that if a Ghanian or Indian patient were to report hearing voices to an American this would be viewed negatively and a symptom of schizophrenia but not if it was to a clinician of there own culture
-leading to low inter-rater reliability
How can cultural bias lead to negative labels
-individuals that display ‘abnormal’ behaviours to a particular culture may be labelled as schizophrenic
-this could lead to confusion as to why and the individual feeling ostracised
-this could result in a self fulfilling prophecy as behaviours such as social withdrawal, avolition and disorganised thinking develop due to negative labelling
what is system overlap and how does it effect reliability
this is when characteristics of a particular disorder are shared with another.
For example depressed mood is a common symptom of schizophrenia and bipolar disorder
This could effect reliability as someone presenting a depressed mood to different clinicians may receive different diagnosis
Describe evidence for symptom overlap effecting reliability of diagnosis
Ross: gave 108 DID patients the ‘positive and negative syndrome scale’
-found patients reported more positive symptoms than schizophrenic patients typically experience
-this can result in those with DID receiving a false-positive diagnosis of schizophrenia as the overlapping symptom is more heavily associated with schizophrenia
-need to ensure enough questions are asked to patients
What is a negative consequence of low reliability due to symptom overlap
-it can lead to misdiagnosis and therefore incorrect therapy
-for example a schizophrenic person with depressive mood may be diagnosed with bipolar
-prescription treatment for bipolar may be ineffective and would also have negative economic implications
how could misdiagnosis due to symptom overlap be avoided
examine the grey content matter of the brain as schizophrenic patients can experience a decrease of grey matter
What is co-morbidity and how can it effect validity
co-morbidity occurs when a person has two or more disorders at the same time for example schizophrenia is often co morbid with disorders such as substance abuse, depression and OCD.
This can affect the validity as it can lead to uncertainty about whether different disorders can be considered independently or not. For example schizophrenia may not always be a separate disorder to depression, depression may be a symptom of schizophrenia
Describe some evidence for co-morbidity effecting validity of diagnosis
Buckley reported that 50% of schizophrenics were co-morbid with depression, 47% with substance abuse and 23% with OCD.
-highlights the problem of trying to distinguish separate disorders
-high levels of co-morbidity might suggest schizophrenia has distinct sub-types for example
What implications does the issue of co-morbidity have
-many schizophrenics are not recognised as having the disorder as clinicians may diagnose only bipolar and not recognise they also have schizophrenia
-this leads to invalid diagnosis and such patients are excluded from research
-research findings may not be representative of sufferers of schizophrenia with co-morbid disorders
What is gender bias and how does it affect validity of diagnosis
Gender bias refers to the differential treatment of males and females based off of pre existing stereotypes.
-males are statistically more likely to be diagnosed with schizophrenia than women
-women typically function better with symptoms such as avolition so may be more likely to ‘cope’ or seek support from others in comparison to men
-this effects validity as clinicians may not recognise some women as suffering with schizophrenia and diagnose them with a different disorder such as depression
Describe evidence for gender bias in diagnosis
Loring: randomly selected 290 psychiatrists and gave them info on two patients, asking them to diagnose them according to standard criteria
results;
-when patients were not assigned a gender or described as male 56% of psychiatrists diagnosed schizophrenia
-when described as female only 20% gave a diagnosis
this highlights that gender bias when interpreting symptoms can affect validity of diagnosis
Describe evidence for a biological basis for the under diagnosis of females
Kulkarni
-found that the female hormone ‘estradiol’ was effective in treating schizophrenia in women when used as an antipsychotic therapy
-suggests female biology naturally helps women cope better with symptoms so may be less likely to seek a clinician
-biological differences between male and female may lead to under-diagnosis of females and therefore reduce validity of diagnosis
What is the polygenic explanation of schizophrenia
suggests the symptoms of schizophrenia are a result of a complex combination of many candidate genes rather than one singular gene or singular combination if genes
Describe the genetic basis of schizophrenia
suggests that our biological characteristics are inherited, therefore mutated genes can be inherited
-candidate genes contribute to the risk of developing sz
-COMT gene is a candidate gene that has been identified, it controls the activity of an enzyme that breaks down dopamine
-low activity variant of COMT means the production of the enzyme is less effective and there is an excess in dopamine activity
-linked heavily to hallucinations
how are twin studies used to investigate the genetic basis of sz
-involves large samples of both monozygotic and dizygotic twins where at least one twin has the disorder
-concordance rates are calculated
-if the concordance rate is higher for monozygotic twins this suggests Theresa genetic basis for sz as mz twins share 100% genetics compared to only about 50% in dz twins
What is a concordance rate in relation to twin studies
the number of twins within a sample who both have the disorder - ususally presented as a percentage
