introduction to schizophrenia

Question 1

diagnosis and classification

Answer 1

• according to medical approach, in order to diagnose specific disorder, need to distinguish one disorder from another
• this is done by identifying clusters of symptoms that occur together and classifying this as one disorder
• diagnosis then possible by identifying symptoms and deciding what disorder someone has

ICD VS DSM -
- two major systems for classification of mental disorder are the WHO’s ICD-10 and the APA’s DSM-5
- previous editions of ICD and DSM recognised subtypes of schizophrenia
- both DSM-5 AND ICD-10 have removed subtypes, they tended to be inconsistent (eg. someone with a diagnosis of paranoid schizophrenia would not show the same symptoms a few years later), now becoming more consistent
- both classify delusions and hallucinations as symptoms
- ICD-11 lists other symptoms such as thought disorders, whereas DSM-5 lists other symptoms such as catatonic behaviour (complete withdrawal from processing external stimuli)
- both state number of symptoms needed for a diagnosis, 2 persistent symptoms needed for a certain duration
- easier to diagnose with ICD because a 6 month period of disturbance is needed to diagnose schizophrenia with DSM, this is a lot longer than the ICD
- ICD-11 is what we use in the UK currently

Question 2

positive symptoms

Answer 2

• positive symptoms are additional experiences beyond those of ordinary existence
• adding to perceptual experience of the world

hallucinations -
- unusual sensory experiences, some related to events in environment whereas some bear no relationship
- can be experienced in relation to any sense, for example may see distorted facial expressions
- usually visual and auditory
- higher activity in parietal and occipital lobes

delusions -
- irrational beliefs
- common delusions involve being an important historical, political or religious figure
- also commonly involve being persecuted
- another class concerns the body, eg. may believe they are under external control

disorganised speech -
- only recognised by DSM
- speech triggers many different schemas

Question 3

negative symptoms

Answer 3

• negative symptoms involve loss of usual abilities and experiences

speech poverty (ICD) -
- changes in patterns of speech
- negative symptom because emphasis is on reaction in amount and quality of speech in schizophrenia
- sometimes accompanied by delay in verbal responses
- more emphasis now placed on speech disorganisation, where speech becomes incoherent or the speaker changes topics mid-sentence
- this is classified in DSM-5 as positive symptom

avolition -
- finding it difficult to begin or keep up with the goal-directed activity
- people with schizophrenia often have sharply reduced motivation to carry out some activities
- Nancy Andreasen identified 3 signs: poor hygiene and grooming, lack of persistence in work or education and lack of energy

Question 4

evaluation strength of diagnosis - good reliability

Answer 4

• psychiatric diagnosis said to be reliable when different clinicians reach same diagnosis and when same clinical reaches same diagnosis for same individual on two occasions
• prior to DSM-5, reliability for diagnosis was low but now improved
• Osorio reported excellent reliability for diagnosis in 180 individuals using DSM-5
• we can be reasonably sure that the diagnosis of schizophrenia is consistently applied

Question 5

evaluation limitation of diagnosis - low validity

Answer 5

• one way to assess validity of psychiatric diagnosis is criterion validity
• Cheniaux had 2 psychiatrists independently assess same 100 clients using ICD-10 and DSM-IV criteria
• found 68 diagnosed with schizophrenia under ICD and 39 under DSM
• suggests that schizophrenia is either over- or underdiagnosed according to diagnostic system, lowering validity

Question 6

evaluation strength of diagnosis - counterpoint to low validity

Answer 6

• in the same study as above, there was excellent agreement between clinicians when using 2 measures to diagnose schizophrenia, both derived from DSM system
• criterion validity for diagnosing schizophrenia is good provided it takes place within a single diagnostic system

Question 7

evaluation limitation of diagnosis - co-morbidity

Answer 7

• if conditions occur together a lot of the time this questions validity of their diagnosis, because they might actually be a single condition
• schizophrenia commonly diagnosed with other conditions such as depression or substance abuse
• problem for classification because schizophrenia may not exist as a distinct condition, problem for diagnosis as some people diagnosed with schizophrenia may have unusual cases of conditions like depression
• 50% co-morbidity with depression

Question 8

evaluation limitation of diagnosis - gender bias

Answer 8

• since 1980s, men diagnosed with schizophrenia more commonly than women
• one possible explanation is that women are less vulnerable than men, perhaps due to genetic factors
• seems more likely that women are under diagnosed because they have closer relationships and hence get support
• this leads to women with schizophrenia often functioning better than men
• this underdiagnosis is gender bias, women may not be receiving treatment and services that might benefit them

Question 9

evaluation limitation of diagnosis - culture bias

Answer 9

• some symptoms such as hearing voices have different meanings in different cultures
• in Haiti, some believe that voices are communications from ancestors
• British people of African-Caribbean origin are 9X more likely to receive diagnosis as white British people, although people living in African-Caribbean countries are not (rules out genetic vulnerability)
• most likely explanation for this is culture bias in diagnosis of clients by psychiatrists from different cultural background, leading to over interpretation of symptoms in black British people
• British African-Caribbean people may be discriminated against by a culturally-biased diagnostic system

Question 10

evaluation limitation of diagnosis - symptom overlap

Answer 10

• considerable overlap between symptoms of schizophrenia and symptoms of other conditions
• both schizophrenia and bipolar disorder involve positive symptoms such as delusions and negative symptoms such as avolition
• for classification, means that schizophrenia and bipolar disorder may not be two different conditions but variations of a single condition
• for diagnosis, means that schizophrenia is hard to distinguish from bipolar disorder
• symptom overlap means that schizophrenia may not exist as distinct condition, even if it does it is hard to diagnose
• classification and diagnosis are flawed