Lesson 1 - Diagnosing schizophrenia Flashcards
(16 cards)
What is schizophrenia?
A psychotic mental disorder characterised by a profound disruption of cognition and emotion. It can affect language, thoughts and perception.
What population of the population have schizophrenia?
1%
What is the DSM-5?
The Diagnostic and Statistical Manual of Psychiatric Disorders used in America
What is the ICD-11?
The International Classification of Diseases used in Europe and other parts of the world
How does the DSM-5 diagnose schizophrenia?
You need to show two or more positive symptoms (like hallucinations and delusions) or one positive and one negative symptom for a month, as well as extreme social withdrawal for at least six months
How does the ICD-11 diagnose schizophrenia?
You need to show one positive and one negative symptom or two negative symptoms for at least a month
Types of schizophrenia
Crow (1980) made a distinction between two types
Type 1 – more positive symptoms (hallucinations, delusions)
Type 2 – more negative symptoms (loss of speech, loss of appropriate emotion).
With type 2 schizophrenia, there are poorer prospects of recovery, as it could be considered easier to remove symptoms than gain skills back
Positive symptoms
- Hallucinations (auditory, tactile, olfactory, visual)
- Delusions – irrational, bizzarre beliefs that seem real to someone with SZ.
- Disorganised speech – could be a result of abnormal thought processes, they cannot organise their thoughts and this shows in their speech. They may slip from one topic to another (derailment) or create ‘word salad’ which is so incoherent that it sounds like gibberish in extreme cases (in the DSM not the ICD)
- Disorganised or catatonic behaviour – inability to motivate or initiate a task. Can lead to problems of personal hygiene or overactivity. Catatonia refers to adopting rigid posture or aimless repetitive behaviours (in the DSM not the ICD)
Negative symptoms
- Speech poverty (alogia) – emphasis on the reduction in the amount and quality of speech. Less complex syntax, shorter sentences for example
- Avolition – or apathy, finding it difficult to begin or keep up with goal-directed activity. Andreason (1982) identified poor hygiene, lack of persistence and lack of energy and signs of this
- Affective flattening – reduction in the range and intensity of emotional expression, like body language and eye contact. May show a deficit in prosody (intonation, tempo, loudness)
- Anhedonia – loss of interest in pleasurable activity, lack of reactivity to normally pleasurable stimuli.
Reliability in diagnosing SZ
- Whaley (2001) found very low inter-rater reliability coefficients between diagnosticians, as low as +0.11 using the DSM.
- Cheniaux et al (2009) asked to independent psychiatrists to diagnose 100 schizophrenic patients with the ICD and DSM:
Psychiatrist 1 – 26 (DSM) : 44 (ICD) Psychiatrist 2 – 13 (DSM) : 24 (ICD) You're more likely to get diagnosed with the ICD than the DSM
- Read et al (2004) reported that test-retest reliability only had a 37% concordance rate and noted a 1970 study where 194 British and 134 US psychiatrists diagnoses patients from case descriptions.
UK - 2% US - 69%
Reliability between psychiatrists is very low and reliability based on the diagnostic method is low
Validity in diagnosing DZ
Rosenhan (1973) – study on being sane in insane places
- Aimed to test the validity of SZ diagnosis with the DSM
- 8 sane volunteers presented themselves to different mental hospitals claiming they could hear voices such as ‘hollow, empty, thud’. All were admitted and acted normally
- The 8 volunteers took between 7 and 52 days to be released, diagnosed as schizophrenics in remission. **Normal behaviours were interpreted as SZ symptoms
- However, 35/118 actual patients suspected that they were sane, but the psychiatrists could not
Later, a hospital was informed that an unspecified number of pseudo-patients would attempt entry over 3 months (lie). 83/193 patients who were admitted aroused suspicion, but no pseudo-patients ever attempted admission
Psychiatrists cannot differentiate between false and real patents
Co-morbidity in diagnosing SZ
Co-morbidity: the idea that two or more mental disorders occur at the same time in the same person
Buckley et al (2009) concluded that around half of patients with SZ also have a diagnosis of :
- Depression (50%) - Substance abuse (47%) - PTSD also occurred in 29% of cases - OCD in 23%.
This poses a challenge for both classification and diagnosing SZ. If half were diagnosed with SZ and depression, this suggests that we are not able to distinguish between the two easily. It may also make very severe depression look like SZ or vice versa.
Symptom overlap in diagnosing SZ
There is a considerable overlap between the symptoms of SZ and other conditions like depression and BPD.
- Ellason and Ross (1995) pointed out that people with DID actually have more schizophrenic symptoms than people diagnosed with SZ.
- Read (2004) suggested that most people diagnosed with SZ have a sufficient number of symptoms of other disorders that they could receive at least one other diagnosis
Gender bias in diagnosing SZ
- Fischer and Buchanan (2017) – Since the 1980s men have been diagnosed with Sz more commonly than women (1.4:1)
- Cotton (2009) –This could be explained as women seem to function better than men, having good family relationships[s and more likely to work. Women have better interpersonal function than men, therefore they are less likely to be diagnosed than men, showing gender bias.
Culture bias in diagnosing SZ
- Pinto and Jones (2008) – African Americans and Afro-Caribbean Brits are 9 times more likely to be diagnosed with SZ
May be because of positive symptoms like auditory hallucinations being acceptable in African cultures due to cultural beliefs in communications with ancestors. This is not as acceptable in the UK and can be seen as an abnormality.
Strengths of classification and diagnosis of SZ
Communication shorthand – makes it easier to incorporate all of the symptoms a patient might be having into a single diagnosis. this makes communication easier between patient and professionals.
Treatment – a reliable diagnosis can point to an appropriate therapy. SZ patients do not respond well to some anti-anxieties, but respond better to some anti-psychotics.
More recent studies – Osario et al (2019) found that inter-rater reliability between psychiatrist pairs was +0.97 and test-retest was +0.92. Shows that the DSM can be reliable.
