Schizophrenia Flashcards
what is scizophrenia?
a serious mental disorder characterised by severe disruptions in psychological functioning.
how can sz be classified?
- the dsm-5 published by the american psychiatric association
- the icd-10 published by the world health organisation
how do the classification systems differ in their classification of sz?
- the dsm requires at least one positive symptom to be present, whereas the icd does not
- the icd recognises a range of subtypes of sz but these were removed from the dsm-5
what is the dsm-5’s criteria for the diagnosis of sz?
criterion a = two or more of the following symptoms must be present for a significant portion of time during a one month period
- delusions
- hallucinations
- disorganised speech
- grossly disorganised catatonic behaviour
- negative symptoms
criterion b = reduction in one or more major areas of functioning eg. work or self care
criterion c = continuous signs of disturbance must persist for 6 months, during which the patient must experience at least 1 month of active symptoms
what are the two types of sz?
type 1 = characterised by positive symptoms
type 2 = characterised by negative symptoms
what is a positive symptom?
what are the positive symptoms?
- any behavioural excess beyond the ordinary experience
- hallucinations = unusual sensory experience. auditory hallucinations (hearing voices) are the more common form experienced by sz patients
- delusions = irrational beliefs that have no basis in reality
what are the two types of delusion?
delusions of persecution = belief that they are being spied on or plotted against
delusions of grandeur = belief that they are an important historical or religious figure
what are the negative symptoms of sz?
any behavioural deficit
- speech poverty (decrease in speech or productivity)
- avolition (decrease in interests and desires, as well as an inability to initiate and persist in goal-directed behaviour)
define what is meant by reliability in sz
the consistency in the diagnosis
what is a weakness of the reliability of the classification of sz?
one weakness is that the reliability of diagnosis using the dsm-5 and the icd-10 is poor. for example, one researcher asked two psychiatrists to independently diagnose 100 patients using both the dsm and the icd. the inter-rater reliability was poor, as using the dsm one psychiatrist diagnosed 26 patients with sz, whilst the other psychiatrist only diagnosed 13. this is a weakness of the diagnostic systems as they failed to produce consistent results.
what is are the strengths of the reliability of sz diagnosis?
one strength of the reliability of sz diagnosis is that resent research has found that it has improved. for example, one researcher reported excellent reliability for the diagnosis of sz using the dsm-5, as pairs of interviewers achieved an inter-ater reliability of .97. this suggests that the diagnostic system is consistently applied and therefore has good reliabilty.
another strength of the reliability of sz diagnosis is that even if the classification systems are not perfect, they provide clinicians with a common language. this enables them to communicate research ideas and findings, which may ultimately lead to a better understanding of the disorder, and the development of more effective treatments
what is co-morbidity?
the presence of one or more additional disorders simultaneously occurring with sz, such as substance abuse, anxiety, and depression. this can lead to different medical professionals giving different diagnoses to the same patient
what is a strength of the issue of comorbidity relating to the classification of sz?
one strength is that there is a large body of evidence to suggest that many sufferers of sz also have issues with substance abuse. for example, one researcher found that around 50% of patients with sz also have depression or substance abuse. alcohol, cannabis and cocaine are substances that can be abused by people with sz, potentially as a way of self medicating. this co-morbid substance abuse makes reliable diagnoses of sz difficult to achieve, and also leads to lower levels of functioning for the sufferer. this is a strength because it demonstrates the complexities involved in giving a reliable diagnosis if the person with sz is also using recreational drugs.
what is culture bias in the diagnosis and classification of schizophrenia?
the extent to which the diagnostic system reflects beliefs about what is viewed as normal and acceptable in western, predominantly white cultures. culture bias reduces the validity of the diagnostic system. both the dsm and the icd were developed by western clinicians and are criticised for lacking cultural relativism.
what is a weakness of the classification of sz in terms of culture bias?
one weakness of the diagnosis of sz is that research suggests it may be affected by culture bias. for example, pinto and jones 2008 reported that in hati, people believe that voices are communications from ancestors (and not positive symptom). similarly, it has been found that british people of african-carribean origin are more likely to receive a diagnosis than british white people - although people living in african-carribean areas are not, thus ruling out genetoic vulnerability. this is a weakness as it highlights the fact that the difference in diagnostic statistics of some cultural groups is due to biased overinterpretations.
similarly, another weakness of the diagnosis of sz is that its diagnosis can differ depending on which country you are in. for example, copeland 1971 gave 134 US and 194 british psychiatrists descriptions of a patient. 60% of the US psychiatrists diagnosed sz, whereas only 2% of the british ones did. this shows that diagnosis is subject to ethnocentric bias.
what is validity in the diagnosis of sz?
the extent to which methods used to measure sz are accurately measuring sz
what is gender bias in sz?
when the accuracy of diagnosis is dependent on the gender of an individual, as the diagnostic material be gender-biased, or clinicians may base their judgements on stereotypical beliefs about gender
what is one weakness of the diagnosis of sz in terms of gender bias?
one weakness is that the diagnosis of sz may be influenced by gender bias. for example, cotton 2009 found that female sz patients function better than male sz patients, as they are more likely to work and have good family relationships. this may explain why women are not diagnosed as frequently as men
what is symptom overlap?
when the symptoms of sz are also found in other disorders, making it difficult for clinicians to accurately decide which disorder someone is suffering from when diagnosing
what is one weakness of symptom overlap in the diagnosis of sz?
- one weakness is that it causes issues when accurately and reliably diagnosing sz.
- one researcher found a genetic overlap between bipolar disorder and sz. three of seven gene locations on the genome associated with sz were also associated with bipolar disorder. this means that both sz and bipolar disorder involve positive symptoms such as delusions and negative symptoms such as avolition. this highlights the problem when trying to distinguish between sz and other illnesses, and in terms of classification it suggests that sz and bipolar disorder may not be separate conditions but variations of a single condition.
another researcher found that people with a disorder called dissociative identity disorder actually display more symptoms of sz than people diagnosed as being schizophrenic. this is a problem as it brings into question whether sz bipolar disorder and DID are separate disorders, or just disorders on the same spectrum.
what are the three biological explanations for schizophrenia?
- dopamine hypothesis
- enlarged ventricles
- genetic explanations
what is the dopamine hypothesis?
- positive symptoms of sz are a result of the overactive transmission of the neurotransmitter dopamine.
- this is because sz sufferers may have abnormally high numbers of d2 receptors on receiving neurons, resulting in more dopamine binding and more neurons firing.
- recent research has found that low levels of dopamine can also be linked to negative symptoms
eg. excess dopamine receptors in Broca’s area (responsible for speech production) may be responsible for auditory hallucinations
what are the strengths of the dopamine hypothesis?
- support from pet scans. Wong found an increased number of dopamine receptors in several brain reigons in patients with sz. this is a strength because it supports the view that sz is caused by unusually high levels of these receptors, increasing the validity of the dopamine hypothesis
- further support from studies into drug use. drugs such as cocaine and amphetamines increase dopamine levels in the brain, causing symptoms in normal people. strength because further supports the view that dopamine is the primary cause of many sz symptoms
- revolutionised the treatment of sz in psychology, providing a practical application. led to the creation of anti psychotic drugs, such as chloropromazine, which reduces the amount of dopamine in the brain and therefore reduces the positive symptoms of sz. strength because success of these drugs strengthens the validity of the dopamine hypothesis.
CA- however, this may not be the case. the drugs affect dopamine levels quickly, however the affect on sz symptoms can take many weeks. this suggests that the cause of sz is more complex than high levels of dopamine.
