Diagnosis and classification of Schizophrenia

Question 1

How is someone diagnosed with Sz?

Answer 1

Symptoms determined

Compares symptoms to classification criteria within a diagnostic tool

Fit criteria = diagnosed with disorder

Question 2

Describe DSM-5?

Answer 2

2 or more symptoms

1 positive symptom needed fro diagnosis if hallucinations are bizarre

6 month period of disturbance with 1 month of criteria A symptoms.

Question 3

Describe ICD-10

Answer 3

Symptoms must persist for at least 1 month

2 or more negative symptoms sufficient under ICD.

Question 4

Define Co-morbidity:

Answer 4

Occurrence of 2 disorders or conditions together
e.g: Sz + personality disorder

Where 2 conditions frequently diagnosed together –> calls into question validity of classifying
2 disorders separately.

Question 5

Define symptom overlap:

Answer 5

Occurs when 2 or more conditions share symptoms.

Conditions sharing many symptoms questions validity of classifying 2 disorders separately.

Question 6

What are the implications of an incorrect diagnosis?

Answer 6

~Social stigma: leads to more stress

~Implications to economy: waste money on treatments e.g: CBTp.

~Prescription of wrong drug –> endangering.

Question 7

Define validity and reliability:

Answer 7

Reliability = consistency

Validity = assess what we are trying to assess

Question 8

What is the difference between face validity and criterion validity?

Answer 8

Criterion: evaluated how accurately a test measures outcome it was designed to measure

Face validity: assessment/test appears to do what it claims to do

Construct validity: How well characteristics of disorder are drawn upon –> allows for accurate statements/predictions

Question 9

Evaluation of diagnosing Sz

Good reliability:

Answer 9

High inter-rater reliability= consistent diagnosis even with different clinicians.

High test-retest reliability = same clinicians reach same conclusions fro same individuals for 2 difference occasions.

Osório et al = excellent reliability for diagnosis of Sz in 180 individuals using DSM 5.

~Inter-rater reliability =+0.97
~Test-retest reliability =+0.92

Consistently applied

Question 10

Evaluation of diagnosis of Sz

Low validity:

Answer 10

1 way to assess validity = criterion validity

Cheniaux (2009) =

2 psychiatrists independently assess same 100 clients using ICD -10 + DSM-IV

Found 68 diagnosed with Sz in ICD

39 under DSM

Sz wither under/over diagnosed according to diagnostic system.

Criterion validity low.

Question 11

COUNTERPOINT:

Low validity?

Answer 11

Osório et al –> excellent agreement when DSM used only

Criterion validity for diagnosing Sz = good if placed in a single diagnostic system.

Question 12

Evaluation for diagnosis:

Gender bias

Answer 12

Fischer + Buchanan (2017)
Since 1980s men been diagnosed with Sz more commonly than women (1.4:! ratio)

Women less vulnerable than men –> genetic factors?

Cotton et al (2009): Women underdiagnosed –> closer relationships = more support.

Women with Sz function better than men. –> Less likely to exhibit disorganised thinking –> social impairment.

Women nor receiving treatment/services that may benefit them.

Question 13

Evaluation of Sz

Culture bias

Answer 13

Symptoms of Sz (hearing voices) = different depending on culture.

Haiti = communications from ancestors.

Brits from Afro-Caribbean origin = 9X more likely to receive Sz diagnosis compared to White Brits. (Pinto+Jones).

African-Caribbean countries are not –> rules out genetic vulnerability.

Leads to over-interpretation of symptoms in Black British people (Escobar 2012)

Racial discrimination by culturally biased diagnostics system.