A2 - schizophrenia Flashcards
what is schizophrenia?
a psychotic disorder where people interpret reality abnormally. It is marked by severely impaired thinking, emotions, and behaviour
what are positive symptoms?
symptoms which are an excess or a distortion of normal functions. In addition to normal experience
what is a negative symptom?
a diminution or loss of normal symptoms
1/3 of patients suffer from significant negative symptoms
what are examples of positive symptoms?
delusions
hallucinations
catatonic or disorganised behaviour
what are examples of negative symptoms?
affective flattening
alogia
avolition
anhedonia
what are delusions and outline 3 types
set of beliefs with no basis in reality e.g. paranoia that they are being stalked
- persecutory
- gandeur
- reference
what are hallucinations and different types?
distorted view/ perception of stimuli
can be auditory, visual, tactile
what is psychomotor behaviour?
stereotypical rocking back and forth, twitches and/or repetitive behaviours
what is disorganised speech?
rapid, loss of focus ‘word salad’ incoherent sentences ‘derailment’
what is affective flattening?
lack of showing emotion, characterised by an unchanging facial expression and little to no change in tone, strength, pitch
what is alogia?
abnormally low level of the frequency and quality of speech
what is avolition?
lack of motivation - inability to cope with the normal pressures and motivations associated with everyday tasks
what is anhedonia?
loss of pleasure - not finding joy in anything
what are the 2 main diagnostic tools for schizophrenia?
DSM-V
ICD-11
what is the criteria on the DSM-V for schizophrenia
symptoms for at least 1 month - requires at least 2 or more of: delusions, hallucinations, disorganised speech, and catatonic behaviour
what is the criteria on the ICD-11 for schizophrenia?
1 month + symptoms - the clinical picture is dominated by relatively stable, often paranoid delusions, usually accompanied by hallucinations
what is reliability?
the extent to which a finding can be consistent
what are the 2 ways reliability can be tested
- test-retest
- inter-rater reliability
what is schizophrenia’s KAPA score?
0.46
what was found about cultural differences in diagnosis?
Copeland et at gave a description of the same patients to 134 US and 194 UK psychiatrists and
69% of US diagnosed them but only 2% of the UK did
what was found about the different variations of ‘hearing voices’ by Luhrman et al
He interviewed 60 adults, 20 from Ghana, India, and US each. The Indians and Ghanaians said they heard playful, advice diving voices. Whereas the Americans reported voices as being violent and hateful. Indicative of being ‘sick’
Evidence that DSM-V shows low reliability AO3
P - despite claims of better reliability as the DSM has been regularly updated since the DSM-III, 30 years ago, there is still little evidence that DSM-V is used reliably by clinicians
E - Whaley found inter-rater reliability correlations in diagnosis as low as 0.11/ For results to be reliable, there must be a 0.7 KAPA score, or a 0.8 inter-rater reliability.
E - these findings suggest, with the lack of objective measures used by other branches of medicine, there continues to be low reliability in the diagnosis of SZ
define validity
the extent to which we are measuring what we are intending to measure
how does Rosenhan’s research demonstrate a lack of validity in the diagnosis of schizophrenia?
Pseudo patients reported hearing voices saying ‘hollow, empty, thud’ at several US psych hospitals.
11/12 times fake patients were diagnosed as insane, showing a lack of validity as they were all fave patients and none had SZ
how does gender bias affect the validity of diagnosis for schizophrenia
critics of the DSM diagnostic criteria argue that some diagnostic categories are biased towards diagnosing one gender rather than the other, therefore lack validity
supporting evidence for how gender bias affects the validity of diagnosis for schizophrenia AO3
E - Loring and Powell randomly selected 290 male and female psychiatrists to read patiend behaviour. Then, were asked to give their diagnosis using a standard criteria.
E - when said to be male or no gender, 56% were diagnosed with SZ
when they were said to be female, only 20% were diagnosed
E - this gender bias did not appear to be evident amongst the female psychiatrists. This suggests that diagnosis is influenced not only by the gender of the patient but the gender of the clinician. It may be that men are more likely to be diagnosed due to gender bias with women’s issues not being taken seriously
what is symptom overlap?
the extent to which symptoms of schizophrenia are also found in other disorders e.g. old, depression, bipolar disorder
AO3 of how symptom overlap can cause problems with making a valid diagnosis of SZ
P - symptom overlap can cause problems with making a valid diagnosis of SZ
E - this suggests that many people diagnosed with sz have enough symptoms of other disorders that they could receive an incorrect diagnosis
E - Ketter identified that misdiagnosis due to symptom overlap can lead to years of delay in receiving correct treatment, during which time further suffering can occur.
L - focussing on resolving this could save money for the NHS and lives of patients
what is co-morbidity?
the extent that 2 or more conditions can occur at the same time
example (Buckley) of co-morbidity
suggested co-morbid depression occurs in 50% of patients with SZ and 47% experience substance abuse
what is likely to contribute to the risk of developing schizophrenia?
variations in candidate genes
what were the findings of concordance rates in family studies for
spouse
child
DZ twins
MZ twins
spouse - 1%
child - 13%
DZ twins - 17%
MZ twins - 48%
AO3 flaw in the argument that MZ and DZ share equally similar environments
Joseph pointed out that MZ twins are treated more similarly, encounter more similar environments and experience more ‘identity confusion’ being treated as ‘the twins’ rather than 2 individuals
what was an adoption study on schizophrenia?
Tienari et al
used two groups, one of 164 adoptees whose mother did have SZ (11 of these also received a diagnosis)
- control group of 197 non sz mothered children (only 4 were later diagnosed)
shows that the genetic liability to schizophrenia had been ‘decisively confirmed’
what is the dopamine hypothesis?
suggests that hyperdopaminergia (high dopamine levels) in the sub-cortex is responsible for schizophrenia
abnormally high numbers of dopamine receptors (D2) on some receiving neurones leads to greater neuronal activity
what is the revised dopamine hypothesis?
hyper and hypo dopaminergia is different areas of the brain contribute to development of sz
what may be responsible for the positive symptom of auditory
hallucinations?
Hyperdopaminergia in the mesolimbic area and Broca’s area
due to the overactivity of neurotransmission
in the auditory areas.
what may be responsible for negative symptoms of sz, such as speech poverty and avolition.
And why
hypodopaminergia in the prefrontal cortex
The prefrontal cortex is associated with logical thinking, so abnormally low dopamine levels in this area may impair the ability to construct sentences (speech poverty) or to make decisions about how to function in day to day
living (avolition).
what are agonist drugs and what effect do they have on the symptoms of schizophrenia?
drugs that increase dopamine activity such as amphetamines or parkinsons drugs can lead to a development of positive SZ symptoms
what are antagonist drugs and what effect do they have on the symptoms of schizophrenia?
decrease dopamine activity by blocking pathways, lead to a reduction in symptoms such as hallucinations and delusions
support evidence for the idea that dopamine impacts SZ symptoms AO3
P - most supporting evidence arises from the results from drug treatments. Medication attempts to alter the activity of dopamine in the brain. Antipsychotic drugs are successful as they reduce symptoms.
E - a meta-analysis carried out by Leucht et al involved the analysis of 212 studies. A comparison of antipsychotic drugs with placebo found all drugs tested were more
effective than the placebo in treating positive and negative symptoms of Sz.
E - this demonstrates effectiveness of antipsychotic drugs in the treatment of schizophrenia
evidence against the dopamine hypothesis AO3
P - however, there is evidence against the dopamine hypothesis
E - Noll found that antipsychotic drugs only reduced all of the symptoms in 20% of patients.
E - this suggests the dopamine activity is not the sole cause of positive symptoms, and other factors may play a role
what is the explanation of abnormal brain structure to explain schizophrenia?
Johnstone et al found that people with sz have larger than average ventricles in the brain. This may be due to areas of the brain dying and ventricles enlarging to take up the extra space