classification of schizophrenia

Question 1

how common is schizophrenia?
at what age are symptoms found usually?
what gender are more likely to develop the disorder?

Answer 1

1% of the population have schizophrenia
symptoms are normally seen around 15-45 years old
men are more likely to develop schizophrenia and are more likely to have an earlier onset

Question 2

how is schizophrenia diagnosed?

Answer 2

diagnosed using the DSM-V or ICD-10 - these both have different definitions of schizophrenia making reliability difficult
has no one defining characteristic but a cluster of unrelated symptoms

Question 3

what are positive symptoms?

Answer 3

experiences that are in addition to normal experiences

Question 4

what are negative symptoms?

Answer 4

loss of normal experiences and abilities

Question 5

positive symptoms of schizophrenia

Answer 5

hallucinations and delusions

Question 6

what are hallucinations?

Answer 6

unusual sensory experience
such as seeing distortions in objects that look like faces or hearing critical voices

Question 7

what are delusions?

Answer 7

irrational beliefs about themselves or the world
e.g. grandeur (believing they are royalty)
paranoia (believing someone is after them)
external control (government is controlling them)

Question 8

negative symptoms of schizophrenia

Answer 8

avolition
speech poverty

Question 9

what is avolition?

Answer 9

a lack of goal-directed behaviour
generally apathetic
three signs of avolition: poor hygiene, lack of persistence in work/education and lack of energy

Question 10

what is speech poverty?

Answer 10

loss of quality and quantity of verbal responses

Question 11

what is reliability?

Answer 11

how consistent the results are using the same measuring tool

Question 12

what factors affecting reliability must be assessed when diagnosing someone with schizophrenia?

Answer 12

inter-rater reliability - two doctors giving the same diagnosis
test-retest reliability - same doctor giving same diagnosis over time with the same symptoms

Question 13

evaluation point: low reliability in diagnosis

Answer 13

Beck (1963) reviewed 153 patients diagnosed by multiple doctors
found only a 54% concordance rate between doctors assessment
suggests low inter-rater reliability in the diagnosis of schizophrenia
suggests people may be incorrectly diagnosed and be receiving inappropriate treatment

Question 14

evaluation point: low reliability in diagnosis

Answer 14

Cheniaux et al had two psychiatrists independently diagnose 100 patients using DSM and ICD criteria
found that inter-rater reliability was poor
one psychiatrist diagnosed 26 patients with schizophrenia using DSM and 44 using ICD
the other diagnosed 13 using DSM and 24 using ICD
suggests inconsistency in classification and diagnosis of schizophrenia which can have dire consequences for patients

Question 15

what is validity?

Answer 15

the accuracy of the diagnosis of schizophrenia

Question 16

what factors affecting validity must be assessed when diagnosing someone with schizophrenia?

Answer 16

co-morbidity
symptom overlap
gender bias
culture bias

Question 17

what is co-morbidity?

Answer 17

co-morbidity - the fact that two or more conditions occur together - questions whether the diagnosis is valid or may be 1 single condition

Question 18

what is symptom overlap?

Answer 18

the existence of overlapping symptoms with other conditions
e.g. common overlap between schizophrenia and bipolar as positive and negative symptoms are similar

Question 19

what is gender bias?

Answer 19

when a person faces unfair disadvantages (or benefits from unearned advantages) because of their gender

Question 20

what is culture bias?

Answer 20

the tendency to judge (or diagnose) people in terms of one’s own cultural assumptions.

Question 21

evaluation point for low validity in diagnosis: co-morbidity

Answer 21

Buckley (2009) found high co-morbidity rates with schizophrenia:
depression 505
drug abused 47%
PTSD 29%
as well as complicating treatment plans
suggests that the original diagnosis of schizophrenia may be in error if the disorders share symptoms

Question 22

evaluation point for low validity in diagnosis: symptom overlap

Answer 22

overlapping symptoms of schizophrenia and bipolar disorder suggests that they may not be separate conditions but variations of a single condition
making it hard to distinguish between the two when it comes to classification and diagnosis

Question 23

evaluation point for low validity in diagnosis: gender bias

Answer 23

Cotton et al suggested that women are less likely to be diagnosed with schizophrenia because they have more support and closer social and familiar relationships than men
meaning that women with schizophrenia function better than men - this may lead to underdiagnosing schizophrenia due to symptoms being masked
suggests that validity of diagnosis is poor because procedures for diagnosis are only effective for men

Question 24

evaluation point for low validity in diagnosis: culture bias

Answer 24

Afro-Caribbean people living in the UK are up to 10x more likely to receive a diagnosis compared to white British people
not due to genetic vulnerability but due to culture bias when diagnosing
some symptoms of schizophrenia like hearing voices have different meanings in different cultures
some cultures may attribute voices to communication from ancestors
but psychiatrists from a different culture may see this as bizarre or irrational
meaning Afro-Caribbean people may be discriminated against by a culturally biased diagnostic system