Schizophrenia Content Booklet 2024 PDF

Psychology​​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Paper 3 SCHIZOPHRENIA CONTENT BOOKLET SPECIFICATION ​ Classification of schizophrenia. Positive symptoms of schizophrenia, including hallucinations and delu...

Psychology​​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Paper 3 SCHIZOPHRENIA CONTENT BOOKLET SPECIFICATION ​ Classification of schizophrenia. Positive symptoms of schizophrenia, including hallucinations and delusions. Negative symptoms of schizophrenia, including speech poverty and avolition. Reliability and validity in diagnosis and classification of schizophrenia, including reference to co-morbidity, culture and gender bias and symptom overlap. ​ Biological explanations for schizophrenia: genetics and neural correlates, including the dopamine hypothesis. ​ Psychological explanations for schizophrenia: family dysfunction and cognitive explanations, including dysfunctional thought processing. ​ Drug therapy: typical and atypical antipsychotics. ​ Cognitive behaviour therapy and family therapy as used in the treatment of schizophrenia. Token economies as used in the management of schizophrenia. ​ The importance of an interactionist approach in explaining and treating schizophrenia; the diathesis-stress model. 1  CLASSIFICATION OF SCHIZOPHRENIA Symptoms of Schizophrenia Schizophrenia is a mental disorder reportedly suffered by 1% of the world population and most commonly diagnosed between the ages of 15 and 35. The condition can affect a sufferer’s thought processes, physical functions and perception of reality. The symptoms of schizophrenia can vary drastically between individual sufferers in terms of their type and severity. Furthermore, some sufferers may only encounter symptoms sporadically, whereas for others, these are more persistent. Positive Symptoms of Schizophrenia The characteristics of schizophrenia include positive symptoms. These are symptoms in addition to normal functioning. They include hallucinations and delusions. Hallucinations are unusual perceptions of environment stimuli unique to the individual, which no one else can perceive. Hallucinations are usually auditory (e.g. hearing voices), but may also be visual (e.g. seeing lights or objects), olfactory (e.g. perceiving a disgusting smell) or tactile (e.g. feeling something or someone is touching the skin). Delusions are irrational beliefs that seem real, but are not true in reality. Paranoid delusions commonly involve an individual believing they are being persecuted by others (e.g. they are being followed or spied upon). Delusions of grandeur involve exaggerated beliefs about one’s own abilities or importance (e.g. being famous or having superpowers). Negative Symptoms of Schizophrenia Negative symptoms involve a reduction in normal functioning. They include avolition and speech poverty. Speech poverty is a significant reduction in the amount or quality of what is spoken. This may involve reduced verbal fluency (e.g. difficulty with saying a list of words for a given topic), reduced language complexity (e.g. short utterances), or a notable delay in verbal responses during a conversation. Avolition (or ‘apathy’) is the difficulty to begin and maintain goal directed behaviour. This involves significantly reduced self-motivation to take part in activities despite having the opportunity to do so (e.g. Choosing to sit on one’s bed for many hours rather than going to work which is a short walk away). 2  Reliability and Validity in the Diagnosis and Classification of Schizophrenia NOTE: The four issues named on the specification can be linked to reliability and validity. Below, each issue is linked to reliability or validity to make the content more manageable and avoid repetition. Reliability in the Diagnosis and Classification of Schizophrenia AO1 In the context of diagnosis, reliability refers to the consistency of measuring the symptoms of schizophrenia. It can be assessed in a number of ways: Test-retest reliability is the extent to which a clinician makes the same diagnosis of schizophrenia on separate occasions from the same information provided by the patient. Inter-rater reliability is the extent to which different clinicians independently make the same diagnosis of schizophrenia for the same patient. CULTURE BIAS as an Issue Affecting the Reliability of Diagnosis AO1 Culture bias concerns differential treatment towards ethnic groups. There is a tendency for members of certain ethnic minorities to be over-diagnosed with schizophrenia. For example, people of Afro-Caribbean descent are several times more likely than white people to be diagnosed with schizophrenia. This could be because the people who create diagnostic tools such as the DSM are from predominately white backgrounds, with a different set of norms and values to other ethnic groups. Cultural bias can therefore affect the inter-rater reliability of diagnosis and classification because an individual reporting the same symptoms to clinicians from different cultural backgrounds may not receive the same diagnosis. AO3 Evidence for cultural bias affecting reliability of diagnosis: Luhrmann et al. (2015) interviewed 60 adults (20 each from Ghana, India and US) diagnosed with schizophrenia about the voices they heard. Many of the Ghanaian and Indian participants reported positive experiences (e.g. the voices were ‘playful’), whereas not one American did (e.g. the voices were ‘hateful) so thought this was a sign that they were ill. The results imply that if a Ghanaian or Indian patient was to report hearing voices to an American clinician, this might be viewed as a bad experience and a symptom of schizophrenia but they would not receive a diagnosis by a clinician from their own culture. This could lead to low inter-rater reliability of diagnosis between clinicians of these particular cultures. AO3 Ways to reduce cultural bias in diagnosis: To reduce the chance of culture bias affecting diagnosis clinicians should be trained to understand how people from different cultures might present their symptoms. Standardised diagnostic questions could also be used during a clinical interview to ensure patients receive a reliable assessment regardless of the cultural background of themselves or their clinician. 3 SYMPTOM OVERLAP as an Issue Affecting the Reliability of Diagnosis AO1 Symptom overlap occurs when the characteristics of a particular disorder are shared with another. For example, schizophrenia and bipolar disorder are often characterised by the common symptom of depressed mood. This can affect the inter-rater reliability of diagnosis because if a person presents the symptom of depressed mood to different clinicians, one may provide a diagnosis of schizophrenia and another with bipolar disorder. AO3 Evidence for symptom overlap affecting reliability of diagnosis: Ellason and Ross (1995) gave 108 patients with a diagnosis of dissociative identity disorder (DID) the ‘Positive and Negative Syndrome Scale’. They found that the patients actually reported more positive symptoms than schizophrenic patients typically experience. The consequence for real patients with DID is they are often provided with a false-positive (type 1 error) diagnosis of schizophrenia because the overlapping positive symptoms are more commonly associated with schizophrenia. If an initial diagnosis is provided without asking the patient enough questions, this can lead to low inter-rater reliability between clinicians. AO3 Inappropriate medication is a negative consequence of low inter-rater reliability due to symptom overlap: An implication of the issue of symptom overlap is that it can lead to misdiagnosis and consequently an incorrect therapy. For example, a schizophrenic patient with depressed mood may be misdiagnosed with bipolar disorder and receive a prescription for this disorder. This treatment may be ineffective and would also have negative economic implications for society. One way to deal with this issue may be to examine the grey matter content of the brain, as schizophrenics can experience a decrease of grey matter, while bipolar sufferers do not. This shows how objective, empirical evidence can support a more unreliable diagnosis of schizophrenia based on symptoms alone. Validity in the Diagnosis and Classification of Schizophrenia AO1 In the context of diagnosis, validity concerns the accuracy of measuring symptoms and whether classification systems can distinguish schizophrenia form other disorders. The validity of a diagnosis of schizophrenia can be assessed in a number of ways: Concurrent validity is the extent to which different classification systems identify symptoms of schizophrenia according to their criteria and the systems arrive at the same diagnosis of schizophrenia. If both systems agree, the diagnosis has concurrent validity. Predictive validity is the extent to which a diagnosis of schizophrenia leads to a treatment which is successful in reducing a patient’s symptoms. If the treatment outcome is successful, the diagnosis has predictive validity. 4 CO-MORBIDITY as an Issue Affecting the Validity of Diagnosis AO1 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 of classification and diagnosis because it leads to uncertainty about whether such 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 and therefore occur at the same time. AO3 Evidence highlighting the issue of co-morbidity in diagnosis: Evidence why co-morbidity affects the validity of diagnosis of schizophrenia in provided by Buckley et al. (2009). They reported that 50% of schizophrenics had co-morbid depression, 47% substance abuse and 23% OCD. This highlights the problem of trying to distinguish separate disorders and that such high levels of co-morbidity might suggest that schizophrenia consists of distinct sub-types. For example, schizophrenia with obsessive-compulsive symptoms may be one such sub-type which should be considered distinct from schizophrenia with substance abuse. AO3 Schizophrenics with co-morbid disorders are excluded from research. An implication of the issue of co-morbidity is that despite being the majority of patients, many schizophrenics are not recognised as having the disorder. This is because a clinician may diagnose a patient with their co-morbid disorder such as bi-polar disorder and not recognise that they also have schizophrenia. This means the diagnosis is invalid and such patients are excluded from research into schizophrenia and any research findings obtained may not represent sufferers of schizophrenia with prominent co-morbid disorders. GENDER BIAS as an Issue Affecting the Validity of Diagnosis AO1 Gender bias refers to differential treatment or representation of males and females, based on stereotypes. In the context of diagnosing schizophrenia, males are statistically more likely to be diagnosed than females. However, this may misrepresent the true prevalence of the disorder for each sex. For instance, female patients typically function better than males when suffering with symptoms such avolition, so may cope or seek support from others. This affects the validity of diagnosis because clinicians may assume women who present such symptoms are not likely to be suffering from of schizophrenia and diagnose them with a different disorder such as depression. 5 AO3 Evidence that gender bias affects the validity of diagnosis: Evidence for gender bias in diagnosis was investigated by Loring and Powell (1988). They randomly selected 290 psychiatrists and asked them to read information about two patients and diagnose them according to standard diagnostic criteria. When the patients were not assigned a gender or described as ‘males’ 56% of the psychiatrists gave a diagnosis of schizophrenia compared to only 20% when they were described as ‘female’. This shows that gender bias when interpreting symptoms can affect the validity of diagnosis. AO3 Evidence for a biological basis for gender differences in diagnosis: There may be a biological reason why females are less likely to be diagnosed with schizophrenia. Kulkarni et al. (2001) found the female hormone oestradiol was effective in treating schizophrenia in women when used as an antipsychotic therapy. This suggests that female biology naturally helpsthem cope better with schizophrenic symptoms than males so they may be less inclined to seek a clinical consultation. This suggests that biological differences between the sexes may therefore lead to under-diagnosis of females and reduce the validity of diagnosis. Exam Questions 1. What terms are used by psychologists to describe A and B below? [2 marks] [AL 2021] AO1 A When a person has two or more disorders at the same time. B When two different disorders have a symptom in common. 2. Outline one negative symptom of schizophrenia. [2 marks] [AL 2019] AO1 3. In the context of schizophrenia, outline what is meant by co-morbidity. [2 marks] [AL 2018] AO1 4. Explain how symptom overlap might lead to problems with the diagnosis and/or classification of AO1 schizophrenia. [2 marks] [AL 2018] 5. Janelle has been diagnosed as suffering from schizophrenia. It began when she started hearing AO2 voices in her head criticising her behaviour and she became convinced that she had been chosen by alien beings for a special purpose. Friends noticed that it became increasingly difficult to make sense of Janelle’s speech and she would give only brief answers to their questions. She also became untidy and unenthusiastic about life in general, spending hours pacing up and down her room. Make reference to the scenario above concerning Janelle to identify negative and positive symptoms of schizophrenia. [4 marks] [Lawton] 6. Briefly outline and evaluate one study of validity in relation to diagnosis of schizophrenia. AO1 [4 marks] [AL 2020] 6  AO3 7. Discuss reliability and/or validity in relation to the diagnosis and classification of schizophrenia. AO1 [8 marks] [AL SQP2] AO3 8. Outline and evaluate culture and gender bias in the diagnosis and classification of schizophrenia. AO1 [16 marks] [Lawton] AO3 BIOLOGICAL EXPLANATIONS OF SCHIZOPHRENIA Genetic Basis of Schizophrenia The genetic basis of schizophrenia suggests that biological characteristics are inherited from parents. A faulty version of a gene initially occurs due to random mutation, but this can then be inherited by the individual’s offspring. Many candidate genes have been identified that contribute to the risk of developing schizophrenia. An example candidate gene underlying schizophrenia is the COMT gene (located on chromosome 22) which controls an enzyme that breaks down dopamine. If a person inherits a low activity variant of the COMT gene, the enzyme is less effective, so dopamine levels are allowed to increase. Excessive dopamine activity has been linked to hallucinations, which are a symptom experienced by some schizophrenic patients. A polygenetic explanation proposes that symptoms of schizophrenia are a result of a complex combination of many candidate genes and that no single gene is responsible. One way of investigating the genetic basis of schizophrenia is through twin studies. These involve large samples of monozygotic (identical) twins and dizygotic (non-identical) twins when one of the twins has been diagnosed with schizophrenia. Concordance rates are then calculated separately for the MZ and DZ samples, which is the number of twins within each sample who both have the disorder, usually represented as a percentage. If the concordance rate is significantly higher for MZ twins than for DZ twins, this suggests schizophrenia has a genetic basis because MZ twins share 100% of their genetic material, whereas DZ twins share approximately 50%. Gottesman (1991) reviewed over 40 twin studies and found the average concordance was 48% for MZ twins and 17% for DZ twins, which suggests schizophrenia is at least partly genetic. 7  Evaluation of the Genetic Basis of Schizophrenia Twin studies provide conflicting evidence for the role of genes: Joseph (2004) conducted a meta-analysis of all twin study data prior to 2001. This reported a MZ twin concordance rate of 40% compared to 7% for DZ twins. Since MZ twins are genetically identical and the concordance rate is significantly higher compared to DZ twins, this strongly supports the role of genes in schizophrenia. However, because the concordance rate for MZ twins was not close to 100%, this suggests schizophrenia is not purely genetic. Overall the findings indicate that although genetics are strongly involved in schizophrenia they are not the sole cause of the disorder and that other factors may be involved. Methodological criticism of investigating genes in cohabiting family members: A methodological issue of investigating concordance rates between family members living together is the fact that they are often affected by similar environmental influences. For example, siblings of a similar age may experience a similar level of overprotection from their parents and lead them to both develop social withdrawal, which is a symptom of schizophrenia. The regularly reported high concordance rates for schizophrenia between related individuals could therefore be due to exposure to family dysfunction and not genes. It is difficult to disentangle the comparative influences of heredity and environment because both factors affect individuals throughout their lifetime. This reduces the validity of research into the genetic basis of schizophrenia because environmental factors confound the results. Adoption studies provide evidence for the genetic basis of schizophrenia: Tienari et al.’s (2000) Finnish adoption study provides additional support for the genetic basis of schizophrenia. They found that 7% of the adopted children with schizophrenic mothers were diagnosed with the disorder, whereas only 2% of the adopted children with non-schizophrenic mothers received a diagnosis. Although both percentages were small, the prevalence of schizophrenia is 3 times higher for the children with a biological mother with the schizophrenia. Furthermore, this is convincing evidence because the related individuals lived apart so the similarity in symptoms is less likely to be due to living in the same environment and is a more valid way of measuring the influence of genes on schizophrenia. Purely genetic explanations are overly deterministic: An additional limitation of the genetic explanation is it is overly deterministic to assume that a child that who inherits a particular combination of genes will suffer from schizophrenia. Genes may predispose an individual to develop the biology that makes them vulnerable to the disorder; however, they may demonstrate free will by making particular life choices that means they encounter environmental situations that mitigate any potential innate factors. For example, if a child is aware that one of their parents has schizophrenia, they may choose to begin therapy at the onset of schizophrenic symptoms which prevents the disorder from developing. 8  Dopamine Hypothesis of Schizophrenia Dopamine is a neurotransmitter which has many functions in the brain. The dopamine hypothesis of schizophrenia suggests that abnormalities in the dopamine systems involved in movement and attention are responsible. An increase in dopamine activity (hyperdopaminergia) in the subcortex of the brain has been linked to positive symptoms of schizophrenia. One possible cause may be the presence of abnormally high levels of D2 receptors on receiving neurons results in more dopamine binding and therefore more neurons firing. If this increased activity occurs in Broca’s area (responsible for speech production) this could to lead to auditory hallucinations and speech difficulties (such as word salad) which are symptoms of paranoid and disorganised schizophrenia. A decrease in dopamine activity (hypodopaminergia) in the cortex has been linked to negative symptoms of schizophrenia. Decreased activity in the prefrontal cortex which is responsible for thinking and decision making can be linked to cognitive deficits (such as derailment) which characterise disorganised schizophrenia. Evaluation of the Dopamine Hypothesis of Schizophrenia Supporting evidence for the dopamine hypothesis: A great deal of supporting evidence for the role of dopamine comes from studying the effects of drugs on the symptoms of schizophrenia. Typical antipsychotic drugs (such as chlorpromazine) have an antagonistic effect by blocking dopamine receptors. Thornley et al. (2003) reviewed 13 trials (1121 participants) and found that chlorpromazine was associated with better overall functioning and reduced symptom severity. This suggests that an abnormally high level of dopamine activity is linked to schizophrenia. Inconclusive evidence for the dopamine hypothesis: The fact that other neurotransmitters may be involved in schizophrenia has led to the evidence for the role of dopamine being inconclusive. Noll (2009) claims antipsychotic drugs only help alleviate symptoms such as hallucinations in one-third of cases. Additionally, some people experience such symptoms despite having normal levels of dopamine activity. This suggests dopamine may be just one of many causal factors involved. Pharmacological applications: A strength of understanding the neurochemical processes involved in schizophrenia is the practical application of developing psychoactive drugs that alter levels of dopamine. For example, the theory that hallucinations may be caused by excessive dopamine activity has led to the development of antagonistic drugs that decrease 9 these levels of activity and ultimately the symptoms of schizophrenia. Such applications can help individuals suffering with schizophrenia to have a better quality of life. The dopamine hypothesis is reductionistic: A limitation of the dopamine hypothesis is that it can be criticised for over simplifying the complex causes of schizophrenia down to the sole action of dopamine. Despite there being two aspects, which together consider the effects of increased and decreased levels of dopamine activity, there are many other neurotransmitters that have been implicated in the causes of schizophrenia other than just dopamine. For example, current research has shifted towards the role of glutamate. Furthermore, the presence of psychological factors can influence the extent to which levels of dopamine affect schizophrenic symptoms for an individual. A particular level of dopamine activity is therefore just one of a number of interacting factors and may not therefore be a complete explanation of schizophrenia. Neural Correlates of Schizophrenia Neural correlates of schizophrenia refers to abnormalities in structural or functional features of the brain which link to particular schizophrenic experiences. Reduced density and volume of grey matter (neuron cell bodies) in the left temporal lobe has been linked to the positive symptom of auditory hallucinations. The upper part of the temporal lobe (superior temporal gyrus) contains the auditory cortex which is involved in perceiving and interpreting speech-based information. Decreased connectivity affects the ability of an individual to realise that internally generated speech is their own ‘inner voice’ and misattribute this to someone else, giving rise to the experience of ‘hearing voices’. Enlarged ventricles (fluid-filled gaps between brain areas) increase in size because of shrinkage or damage to the surrounding brain matter. Enlarged ventricles in central brain areas and the prefrontal cortex have been linked to negative symptoms of schizophrenia such as disorganised thinking and avolition. Evaluation of Neural Correlates of Schizophrenia Research evidence for decreased volume of grey matter: Research evidence supporting the role of decreased grey matter volume of the temporal lobe in schizophrenia is provided by Milev et al. (2003). They performed MRI scans to measure temporal lobe tissue volume of 123 schizophrenics and conducted a correlational analysis in a 5-year longitudinal study. They found smaller temporal lobe grey matter volume was negatively correlated (as the volume of grey matter decreases, persistence of hallucinations increases) with persistence of hallucinations during follow-up, suggesting that hallucinations may have a neurological basis. 10 Research evidence for enlarged ventricles: Research evidence supporting the role of enlarged ventricles in schizophrenia is provided by Ho et al. (2003). They conducted a longitudinal study of structural brain abnormalities using MRI in 73 schizophrenic patients and 23 controls. In a 3-year follow-up they found that negative symptom severity was positively correlated (as ventricles increase, negative symptom severity also increases) with enlargement in frontal lobe cerebrospinal fluid volume (Pearson r = 0.44; n = 70; p