Schizophrenia - Paper 3 Flashcards
What is schizophrenia?
A psychological disorder characterised by loss of contact with reality - it is classified as a psychosis.
Where does schizophrenia occur?
. In around 1% of the population (0.7%)
. More commonly diagnosed in men than women
. More common in urban environments
. More common in working class populations
. Average age of onset is between 25-30 years
What is meant by diagnosis and classification?
To be able to diagnosed with a disorder, psychiatrists must first classify it. This is done by consulting a diagnostic manual to classify the disorder, and then they are diagnosed by identifying their symptoms.
What are the two main classification systems?
DSM-5 and ICD-10
What is the difference between ICD-10 and DSM-5?
ICD-10 - Only negative symptoms need to be present
DSM-5 - Only positive symptoms need to be present
What are the two types of symptoms of schizophrenia?
Positive and Negative symptoms
What are positive symptoms?
Symptoms that aren’t typically present in a normal person. They reflect an excess or distortion of normal thinking
What are negative symptoms?
Symptoms which cause a decline in functioning - where the sufferer looses something they previously had. They reflect a loss of normal functioning
What are the positive symptoms of schizophrenia?
. Delusions - False beliefs which are firmly held despite being illogical or having no supporting evidence. Irrational beliefs
. Hallucinations - Disturbances in perception, where someone senses something this isn’t there or is unusual
. Psychomotor disturbances - Repetitive behaviours, such as twitches or rocking back and forth
. Catatonia
What are the common types of delusions?
. Delusions of persecution
. Delusions of grandeur
. Delusions of control
What are the common types of hallucinations?
Auditory, Visual
What are the negative symptoms of schizophrenia?
. Speech poverty/alogia - Reduction in the quality or quantity of a persons speech HOWEVER speech disorganisation, where speech is incoherent or the speaker changes topic midsentence, is classified as a positive symptom
. Avolition - ‘Apathy’ - where individuals struggle to become motivated or keep up with goal oriented activity. Andreasen (1982) identified three signs of avolition: poor hygiene and grooming, lack of persistence in education/work, lack of energy
What are some strengths of the classification and diagnosis of schizophrenia?
+ High reliability - In terms of psychiatric diagnosis, reliability is achieved when different diagnosing clinicians reach the same diagnosis for an individual (inter-rater reliability) and when the same clinician reaches the same diagnosis for an individual on two occasions (test-retest reliability) - when diagnoses are consistent. Osorio et.al (2019) reported high reliability in the diagnosis of 180 individuals using the DSM-5, where pairs of interviewers achieved inter-rater reliability of +.97 and test-retest reliability +.92. This gives psychologists faith in the diagnosis of schizophrenia, as they can be reasonably sure that it is consistently applied
What are some limitations of the classification and diagnosis of schizophrenia?
- Low validity - Cheniaux et.al (2009) had 2 psychologists independently assess the same 100 clients using ICD-10 and DSM-5. 68 were diagnosed with schizophrenia under the ICD system, and 39 under DSM. This suggests that schizophrenia can be over or under diagnosed according to the diagnostic system, and shows that the criterion validity of diagnostic tools is low. Also demonstrated by Rosenhan (1973) in which 8 psuedopatients were kept in hospital after being falsely diagnosed, despite then behaving normally while in hospital. In a follow up study, doctors rejected genuine patients who they assumed were part of the deception, suggesting that the validity of diagnosis’ might be poor.
—- COUNTER —- The Osorio et.al (2019) study reported excellent agreement between clinicians when the methods used to diagnose schizophrenia both derived from the DSM system. So criterion validity can be high, provided the diagnostic tools come from one system. - Co-morbidity - Conditions often occur at the same time, which challenges the validity of diagnosis and classification, as two conditions may be identified when the patient is actually only suffering from one. Schizophrenia is frequently diagnosed with other conditions, such as depression, substance abuse or OCD (Buckley et.al). Schizophrenia may not exist as a distinct condition, but be a name given to the symptoms of other disorders. This challenges the validity and accuracy of schizophrenia diagnoses.
- Gender Bias - Since the 1980’s men have been diagnosed with schizophrenia more commonly than women (a ratio of 1.4:1, according to Fischer and Buchanan 2017). One possible explanation of this is that women are less vulnerable than men. However it also seems likely that women are underdiagnosed because they have closer relationships, and therefore receive greater support (Cotton et.al 2009) and function better. The methods of diagnosing schizophrenia do not take this into account, meaning that women with schizophrenia may not receive the support they need.
- Culture Bias - Some symptoms of schizophrenia have different meanings within different cultures. For example, hearing voices may be considered abnormal in British culture, but is believed in Haiti to be a communication from ancestors. British people of Afro-Caribbean heritage are up to 9x more likely to receive a schizophrenia diagnosis than their white British counterparts (Pinto and Jones 2008). These rates of diagnosis are not reflected in African-Caribbean countries, ruling out a genetic explanation. This difference could be explained by culture bias in diagnosis, where psychologists from a different cultural background overinterpret symptoms of schizophrenia in black British people (Escobar 2012). As such, the diagnosis system for schizophrenia may be culturally biased, leading to inaccurate diagnosis.
- Symptom overlap - There is considerable overlap between the symptoms of schizophrenia and other mental health disorders. Slater and Roth (1969) say that hallucinations are the least important of all symptoms, as they are not exclusive to schizophrenia. For example, both schizophrenia and bipolar involve both positive symptoms, such as delusion, and negative symptoms such as avolition. This could suggest that it is incorrect to classify them as two separate conditions - they may be variations of the same condition. Symptom overlap means that schizophrenia may not exist as a distinct condition, and that even if it does diagnosis is difficult as it does not have any unique and distinct symptoms, which could lead to inaccurate diagnosis.
What are the biological explanations of schizophrenia?
. Genetic basis of schizophrenia
. Neural correlates
What do family studies show?
Family studies have confirmed that the risk of developing schizophrenia increases in line with genetic similarity to someone with the disorder, as demonstrated by Gottesmann (1991)
What were the findings of Gottesmann (1991)?
As genetic similarity to someone with schizophrenia increases, so does the probability of developing the disorder
. General population - 1%
. Uncles/Aunts - 2%
. Grandchildren - 5%
. Parents - 6%
. Siblings - 9%
. Identical twins - 48%
What are candidate genes?
Genes that are believed to code for a particular disorder. Early research looked into the role of one single faulty gene. However recent research suggests schizophrenia is polygenic, likely involving genes that code for neurotransmitters such as dopamine. The identification of different candidate genes in research into schizophrenia also suggests that it is aetiologically heterogenous ( different combinations of factors, including genetic variations, can lead to the disorder in different people)
What was Ripke et.al (2014)
. Combined all previous data from genome-wide studies of schizophrenia
. The genetic makeups of 37,000 people with a diagnosis of schizophrenia were compared to those of 113,000 controls
. 108 separate genetic variations were found to be associated with increased risk of schizophrenia
What is the role of mutation?
Schizophrenia can have a genetic origin in the absence of family history. One explanation of this is a mutation in the parental DNA, which may be caused by radiation, poison or viral infection. Evidence for mutation comes from positive correlations between paternal age (which is associated with increased risk of sperm mutation) and risk of schizophrenia - from 0.7% with fathers under 25 to over 2% with fathers over 50 (Brown et.al 2002)
What are some strengths of the genetic basis of schizophrenia?
+ Strong evidence base - Family studies such as Gottesman (1991) show that risk of developing schizophrenia increases with genetic similarity to a family member with schizophrenia. This was supported by Tienari et.al (2004) which demonstrated that biological children of parents with schizophrenia have an increased risk of developing the disorder, even when raised in adoptive families. Hilker et.al (2018) also showed a concordance rate of 33% for identical twins, compared to 7% for non-identical twins, supporting the genetic explanation. As such, the theory can be seen as having high reliability, as findings consistently support the theory.
What are some limitations of the genetic basis of schizophrenia?
- There is clear evidence to suggest that environmental factors increase the risk of developing schizophrenia - not just genetic. These environmental factors can include biological influences, such as birth complications (Morgan et.al 2017) and smoking THC rich cannabis in the teenage years (Di Forti et.al 2015), and psychological influences such as childhood trauma. Morkved et.al (2017) found that 67% of people with schizophrenia and related psychotic disorders reported at least 1 childhood trauma, vs 38% of a matched group with non-psychotic mental health issues. Furthermore, the fact that concordance rates for schizophrenia are not 100% means that it cannot be wholly explained by genes. This means that the genetic explanation is an incomplete one, and one that over emphasises nature and ignores nature.
What are neural correlates?
Patterns of structure or activity in the brain that occur in conjunction with an experience. The best known neural correlate of schizophrenia is the neurotransmitter dopamine, which is key in the function of several of the brain systems involved in the symptoms of schizophrenia
What is the original dopamine hypothesis?
. Subcortical Hyperdopaminergia
. Based on the discovery that drugs used to treat schizophrenia - such as antipsychotics which reduce dopamine - cause symptoms similar to those of Parkinson’s disease, which is associated with low dopamine levels (Seeman 1987)
Parkinson’s involves a reduction in dopamine levels, so the drugs used to treat it increase dopamine production - but these drugs worsen symptoms of schizophrenia
. Therefore schizophrenia may be the result of high dopamine levels in the subcortical areas of the brain eg. an excess of dopamine receptors in pathways from the subcortex to Broca’s area - Broca’s area is associated with speech production, so abnormal functioning here could explain symptoms such as speech poverty or auditory hallucinations
What is the updated dopamine hypothesis?
. Cortical Hypodopaminergia
. Proposed by Davis et.al (1991)
. Suggests schizophrenia is the result of abnormally low dopamine levels in the cortex
. Used to explain symptoms of schizophrenia eg. low dopamine in the prefrontal cortex, which is responsible for thinking, could explain some negative symptoms of schizophrenia
. It has been suggested that cortical hypodopaminergia can lead to subcortical hyperdopaminergia - so the updated hypothesis involves both high and low levels of dopamine
. It argues that genetic variations and early experiences of stress make people more sensitive to cortical hypodopaminergia, and by extension subcortical hyperopaminergia ( Howes et.al 2017)
What are some strengths of the dopamine hypothesis?
+ Research support for the role of dopamine in schizophrenia - Curran et.al (2004) found that amphetamines, which increase dopamine levels, worsen symptoms in people with schizophrenia and induce symptoms in people not diagnosed with the disorder. Tauscher et.al (2014) also found that antipsychotic drugs reduce dopamine activity and reduce the intensity of symptoms. Furthermore, several of the candidate genes linked to schizophrenia act on the production of dopamine, or on dopamine receptors. Finally, Tenn et.al (2003) induced schizophrenia like symptoms in rats using amphetamines, and reduced them using drugs that reduce dopamine action. This supports the link between dopamine and schizophrenia, strengthening the dopamine hypothesis.
What are some limitations of the dopamine hypothesis?
- There is also evidence for the importance of other neurotransmitters in causing schizophrenia, notably glutamate - Post-mortem and live brain scan studies have consistently found higher levels of glutamate in several brain regions of people with schizophrenia (McCutcheon et.al 2020). Additionally, several candidate genes for schizophrenia are believed to be involved in glutamate production or processing. The dopamine hypothesis arguably overemphasises the role of dopamine, at the expense of other neurotransmitters, and as a result can be seen as an incomplete explanation.
- Other drugs which increase dopamine levels, such as apomorphine, do not cause schizophrenia-like symptoms (Depatie and Lai 2001). Also, Noll (2009) argued that around 1/3 of patients do not respond to drugs which block dopamine, so other neurotransmitters are causes must be involved.
- Biologically deterministic
What is meant by family dysfunction?
Processes within a family, such as poor family communication, cold parenting, and high levels of expressed emotion, which can be risk factors for the development and maintenance of schizophrenia
What are the 3 types of Family Dysfunction explanation?
. Schizophrenogenic mother
. Double - bind theory
. Expressed Emotion