Schizophrenia Flashcards
What is schizophrenia?
A type of psychosis, a severe mental disorder characterised by a profound disruption of cognition and emotion so that contact with external reality and insight are impaired. This affects a person’s language, thought, perception, emotions and even their sense of self.
How common is schizophrenia?
Affects 1% of the population at some point in their lifetime
What type of disorder is schizophrenia?
Psychotic disorder
When does schizophrenic symptoms typically begin to show?
It can occur any time in life, but usually occurs late in adolescence or early adulthood. The peak of incidence onset is 25-30 years.
What do we mean by classification in the context of schizophrenia?
Organising symptoms into categories based on which symptoms cluster together in sufferers i.e. what are the symptoms of schizophrenia?
What do we mean by diagnosis in the context of schizophrenia?
Deciding whether someone has a particular mental illness using the classifications. (does someone have the symptoms)
Define positive symptoms
Atypical symptoms that are in addition to regular sensory experience
Define negative symptoms
Atypical symptoms that represent a loss compared to regular sensory experience
Define hallucinations
Disturbances of perception in any of the senses. They are false sensory perceptions that have no basis in reality or are a distorted perception of things that are (positive)
Define delusions
False (irrational) beliefs not based in reality or are a distorted perception of things that are (positive)
Define speech poverty
Limited speech output with limited, often repetitive content. It involves reduced frequency (amount) and quality of speech (negative)
Define avolition
A lack of purposeful, willed behaviour. It is the reduction, difficulty or inability to start and continue with goal-directed behaviour i.e. actions performed to achieve a result. (negative)
Give examples of different kinds of hallucinations
Visual - see something that isn’t there
Auditory - hear something that isn’t real
Give examples of different kinds of delusions
Delusions of persecution – the belief that others want to harm, threaten or manipulate you e.g. the government, aliens.
Delusions of grandeur – the belief that they are an important individual, even god-like and have extraordinary powers e.g. the belief that they are Jesus Christ.
Delusions of control – the belief that their body is under external control e.g. being controlled by aliens or the government (e.g. have implanted radio transmitters).
What do we mean by a classification system of schizophrenia?
A cluster of symptoms
There are two classification systems used to classify and diagnose schizophrenia. For each one, name it and explain what combination of symptoms are required for a diagnosis of schizophrenia.
DSM-5 - America - two of the positive symptoms must be present for diagnosis, but only one if delusions are bizarre or hallucinations consist of a voice keeping up a running commentary on the person’s behaviour or thoughts, or two or more voices conversing together. There must be continuous signs of disturbance for at least 1 month. For a significant portion of the time, one or more major areas of functioning such as work, interpersonal relations or self-care must be markedly below the level achieved prior to onset.
ICD-10 - Europe - two or more negative symptoms are sufficient for diagnosis or one positive symptom.
What do we mean by reliability in the context of classifying and diagnosing schizophrenia?
The level of agreement (consistency) on the diagnosis of schizophrenia by different psychiatrists (inter-rater reliability) across time (test-retest reliability) and cultures. It is also the stability of diagnosis over time given no change in symptoms.
What do we mean by validity in the context of classifying and diagnosing schizophrenia?
The extent to which schizophrenia is a unique syndrome with unique characteristics, signs and symptoms (so whether it measures what it intends to measure). Miss Maiden’s note: this includes whether we can tell the difference between schizophrenia and other mental illnesses and whether we can accurately diagnose someone has having schizophrenia when they do and not diagnose them when they don’t.
Describe evidence that the DSM5 is reliable.
Osario et al. (2019) found inter-rater reliability of +0.97 and test-retest reliability of +0.92 for the DSM5 suggesting the diagnosis of schizophrenia is consistently applied.
Define symptom overlap.
When two or more conditions share symptoms.
Give an example of symptom overlap in the classification and/or diagnosis of schizophrenia
Hallucinations, difficulty concentrating and delusions are a part of bipolar disorder
Explain how this impacts the validity of the classification and/or diagnosis of schizophrenia.
Validity of classification - it seems that schizophrenia does not have enough unique characteristics, signs and symptoms to be distinguishable from other mental health problems.
Validity of diagnosis - therefore there may be misdiagnoses as people may not be accurately diagnosed with schizophrenia when they have it, and not diagnosed when they don’t have it.
Describe evidence that supports the symptom overlap is an issue in the validity of the classification and/or diagnosis of schizophrenia.
Ketter (2005) points out that misdiagnosis due to symptom overlap can lead to years of delay in receiving relevant treatment, during which time suffering and further degeneration can occur, as well as high levels of suicide- so symptom overlap can have serious consequences. Focusing on fixing this issue could save money and lives.
Describe evidence that supports that symptom overlap is not a significant issue in the validity of the classification and/or diagnosis of schizophrenia.
Serper et al. (1999) assessed patients with co-morbid schizophrenia and cocaine abuse, cocaine intoxication on its own and schizophrenia on its own. They found that despite there being considerable symptom overlap in patients with schizophrenia and cocaine abuse, it was actually possible to make accurate diagnoses.
Define co-morbidity.
When one person has more than one mental illness at the same time e.g. Schizophrenia and personality disorders
Explain how this impacts the validity of the classification and/or diagnosis of schizophrenia.
Validity of classification - if schizophrenia tends to occur with another mental illness, it doesn’t seem to have enough unique characteristics as a mental health problem to be distinguished from others. Also, if two illnesses tend to occur together, it may be better to class them as one overall illness.
Validity of diagnosis - therefore it’s unlikely that we will be able to accurately diagnose someone with schizophrenia when they have it and as not having it when they don’t.
Describe evidence that supports the co-morbidity is an issue in the validity of the classification and/or diagnosis of schizophrenia.
Buckley et al. (2009) concluded that around half of patients with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%). PTSD also occurred in 29% of cases and OCD in 23%.
What is cultural bias?
A tendency to interpret all phenomena through the lens of one’s own culture, ignoring the effects that cultural differences might have on behaviour.
What makes researchers think that diagnoses of schizophrenia may be culturally biased?
African-Americans and English people of Afro-Caribbean origin are up to 10 times more likely to be diagnosed with schizophrenia. Given that rates in Africa and the West Indies aren’t high (ruling out a genetic vulnerability), the diagnosis seems to be the result of cultural bias.
Positive symptoms of hearing voices may be more acceptable in African cultures because of cultural beliefs in communication with ancestors.
Why might this cultural bias occur?
When reported to a psychiatrist from a different cultural tradition, hearing voices etc is more likely to be seen as bizarre and irrational.
Explain how this impacts the validity and/or reliability of diagnoses of schizophrenia.
This calls into question the validity of diagnoses of schizophrenia as psychiatrists may impose their own cultural standards for schizophrenia onto those from other cultures and so are biased towards what is ‘normal’ in their culture (ethnocentric). Therefore, the diagnoses may not be valid across cultures as any deviation from what is normal in their culture is misinterpreted and mislabelled as a symptom of schizophrenia.
It also calls into question the reliability of diagnoses of schizophrenia as it suggests that there may not be agreement on the diagnosis by psychiatrists across cultures and so the methods may not be suitable for use across all cultures as there wouldn’t be consistent diagnoses/classifications. It suggests that patients can display the same symptoms but receive different diagnoses because of their ethnic background; i.e. a patient’s ethnicity makes it more or less likely that they will be diagnosed with schizophrenia.
Describe two pieces of evidence that support that cultural bias is a significant issue in the reliability and/or validity of the diagnosis of schizophrenia.
Copeland et al. (1971) gave a description of a patient (who is described as being from an ethnic minority) to 134 US and 194 British psychiatrists. 69% of the US psychiatrists diagnosed schizophrenia but only 2% of the British gave the diagnosis of schizophrenia. No research has found any cause for this, so it suggests that the symptoms of ethnic minorities are misinterpreted.
Escobar (2012) has pointed out that White psychiatrists may tend to over-interpret the symptoms of Black people during diagnosis. Such factors as cultural differences in language and mannerisms, difficulties in relating between black patients and white therapists, and the myth that black people rarely suffer from affective disorders may be causing this problem. Therefore, clinicians and researchers must pay more attention to the effects of cultural differences on diagnosis.
What is gender bias in the diagnosis of schizophrenia?
A tendency to treat one individual or group in a different way from others (it may not present the experience or behaviour of one of the genders)
What makes researchers think that diagnoses of schizophrenia may be gender biased?
Longenecker et al. (2010) reviewed studies of the prevalence of schizophrenia and concluded that since the 1980s, men have been diagnosed with schizophrenia more often than women. Prior to this, there had been no difference.
Why might this gender bias occur?
Female patients typically function better than men, being more likely to work and have good family relationships
Explain how this impacts the validity and/or reliability of the diagnoses of schizophrenia.
This calls into question the reliability of the diagnosis of schizophrenia because if patients are seen by different clinicians, they may receive different diagnoses and therefore the diagnoses lack inter-rater reliability. It also questions the validity of the diagnoses of schizophrenia as it suggests that schizophrenia may not accurately be diagnosed when it is present.
Describe evidence that supports that gender bias is a significant issue in the reliability and/or validity of the diagnosis of schizophrenia.
Loring and Powell (1988) randomly selected 290 male and female psychiatrists to read two case articles of patients’ behaviour and then asked them to offer their judgment on these individuals using standard diagnostic criteria. When the patients were described as ‘male’ or no information was given about their gender, 56% were given a diagnosis of schizophrenia. However, when the patients were described as ‘female’, only 20% were given a diagnosis of schizophrenia. This suggests that there is a gender bias in the diagnosis of schizophrenia which calls into question its validity. This gender bias did not appear to be evident amongst the female psychiatrists.
What do we mean by ‘biological explanations’ of schizophrenia?
Biological explanations emphasise the role of inherited factors and dysfunction of brain activity in the development of schizophrenia.
Two explanations are genetics and neural correlates
What do we mean when we say that schizophrenia is genetic?
Inherited
Describe Gottesman’s (1991) study.
Gottesman (1991) conducted a large-scale family and found much higher concordance rates in MZ twins (48%) in comparison to DZ twins (17%). This suggests that individuals with identical genetic make-up (MZ twins) have an increased risk of developing schizophrenia compared to those who share fewer genes, suggesting that there is an association between the degree of genetic similarity and shared risks of schizophrenia.
Explain how this suggests that schizophrenia is genetic using the concordance rates and % of genes the family members share.
MZ twin concordance rate is higher than DZ twin concordance rate and MZ twins more likely to have schizophrenia in common - more genes shared (MZ share 100% and DZ share 50%), more schiz in common
What does the genetic explanation suggest about schizophrenia being polygenic?
Schizophrenia is thought to be polygenic (it requires a number of different genes to work in combination) and so different combinations of genes can lead to the condition. The most likely genes are those coding for neurotransmitters such as dopamine. Research suggests that there are 108 genetic variations associated with increased risk of schizophrenia.
What does the genetic explanation suggest about schizophrenia potentially being the result of a mutation?
Schizophrenia can also have a genetic origin through the mutation of parental DNA by radiation, poison or viral infection. Brown et al. (2002) found a positive correlation between paternal age (which is associated with increased risk of sperm mutation) and risk of schizophrenia, increasing from around 0.7% in fathers under 25 to over 2% in fathers over 50.
What are neural correlates?
Neural correlates are measurements of the structure or function of the brain (including neurotransmitters) that occur in conjunction with (correlate with) the characteristic symptoms of schizophrenia, and so may be implicated in the origins of schizophrenia.
Describe the (revised) dopamine hypothesis.
Dopamine is a neurotransmitter that generally has an excitatory effect and is associated with the sensation of pleasure.
In the original hypothesis, they suggested that the positive symptoms of schizophrenia are caused by higher levels or activity of dopamine in the subcortical areas of the brain (central areas of the brain). Messages from neurons that transmit dopamine fire too easily or too often in those with schizophrenia. Schizophrenics are thought to have abnormally high levels of D2 receptors on post-synaptic neurons, resulting in more dopamine binding and therefore more neurons firing. E.g. an excess of dopamine receptors in Broca’s area may be associated with speech poverty and/or auditory hallucinations.
In the revised version, it was added that the negative symptoms of schizophrenia are thought to arise from lower levels of dopamine in the pre-frontal cortex (e.g. cognitive problems, avolition).
It has been suggested that low levels of dopamine in the cortex may lead to the high levels of dopamine in the subcortical areas of the brain. Therefore, it may be that both high and low levels of dopamine in different brain regions are involved in schizophrenia.
Describe one other neural correlate of schizophrenia.
Lower activation levels in the superior temporal gyrus and anterior cingulate gyrus have been found in those experiencing auditory hallucinations. Therefore, reduced activity in these two areas is a neural correlate of auditory hallucinations (positive symptom).
Describe evidence to support that schizophrenia is genetic. Remember to explain exactly how it supports that schizophrenia is genetic.
Gottesman (1991) conducted a large-scale family and found much higher concordance rates in MZ twins (48%) in comparison to DZ twins (17%). This suggests that individuals with identical genetic make-up (MZ twins) have an increased risk of developing schizophrenia compared to those who share fewer genes, suggesting that there is an association between the degree of genetic similarity and shared risks of schizophrenia.
This supports the idea that genetic factors make some people much more vulnerable to developing schizophrenia than others [remember that you need to explain how exactly]. This does not mean that schizophrenia is entirely genetic, as there are a number of environmental factors associated with risk of schizophrenia, but the available evidence suggests that genetic susceptibility is very important.
Supporting evidence for the genetic explanation can come from twin studies. Why are twin studies not very strong support for the biological explanations of schizophrenia?
The assumption that the greater concordance for schizophrenia between MZ twins is a product of greater genetic similarity rather than greater environmental similarity. However, MZ twins are treated more similarly, encounter more similar environments (e.g. are more likely to do things together) and are frequently treated ‘as twins’ rather than as two distinct individuals than DZ twins.
As a result, the differences in concordance rates between MZ twins and DZ twins may reflect nothing more than the environmental differences that distinguish the two types of twin. As such, the results from twin studies may not provide as strong support for the biological explanations of schizophrenia as previously suggested.
Describe evidence to both support and undermine the dopamine hypothesis. Remember to explain exactly how it supports the hypothesis.
There is evidence to support the dopamine hypothesis from drug treatments. For example Leucht et al. (2013) found that anti-psychotic drugs were significantly more effective than placebos in the treatment of positive and negative symptoms. Dopamine agonists that increase the levels of dopamine make schizophrenia worse and can produce schizophrenia-like symptoms in non-sufferers (Curran et al., 2004). However, Noll (2009) argues that antipsychotic drugs do not alleviate hallucinations and delusions in about 1/3 of people experiencing these symptoms. Also, in some people, hallucinations and delusions are present despite levels of dopamine being normal. Blocking the D2 receptors has little or no effect on their symptoms. Therefore overall, this suggests that rather than dopamine being the sole cause of positive symptoms in the sub cortex, other neurotransmitter systems, acting independently of the dopamine system may also produce the positive symptoms associated with schizophrenia, undermining the dopamine hypothesis as a neural correlate of schizophrenia.
Neural correlates are exactly that - correlates. Why is that a problem when it comes to explaining schizophrenia?
Correlations don’t show cause and effect (Although studies of neural correlates are useful in flagging up particular brain systems that may not be working properly, this kind of evidence does not prove that the activity in the brain region causes the symptom. For example, whilst it may be that something wrong in the ventral striatum causes the negative symptoms, it is possible that the negative symptoms themselves mean that less information passes through the striatum resulting in its reduced activity. It’s also possible that another factor influences both.
Describe evidence to support that schizophrenia is not entirely biological?
Many researchers now accept that the fact that schizophrenia appears to run in families may be more to do with common rearing patterns or other factors that have nothing to do with heredity. After all, the probability of developing schizophrenia even if your identical twin has it is less than 50%. For example, childhood trauma may make people more vulnerable to schizophrenia. Morkved et al. (2017) found that 67% of people with schizophrenia and related psychotic conditions reported at least one childhood trauma compared to 38% of a matched group with non-psychotic mental health problems.
This suggests that whilst a genetic vulnerability for schizophrenia may be important, psychological factors beyond genetics are also important and so the biological explanations alone cannot be considered to be complete explanations of schizophrenia. It may be better to take an interactionist approach, combining biological and psychological factors.