Diagnosis & Classification Flashcards
DSM-5 and ICD-10
There are two main classification systems in use:
1) DSM-5 - one positive symptom must be present (delusions, hallucinations or speech disorganisation).
2) ICD-10 - two or more negative symptoms are sufficient for diagnosis (e.g. avolition and speech poverty).
Positive Symptoms
Additional experiences beyond those of ordinary existences.
HALLUCINATIONS
1) Unusual sensory experiences that have no basis in reality or distorted perceptions of real things. Experienced in relation to any sense.
E.g. hearing voices or seeing people who aren’t there.
DELUSIONS
2) Beliefs that have no basis in reality - make a person with schizophrenia behave in ways that make sense to them but are bizarre to others.
E.g. beliefs about being a very important person or the victim of a conspiracy.
Negative Symptoms
Loss of usual abilities & experiences.
SPEECH POVERTY
1) A reduction in the amount and quality of speech. May include a delay in verbal responses during conversation.
–> BUT DSM emphasises speech disorganisation and incoherence as a positive symptom.
AVOLITION
2) Severe loss of motivation to carry out everyday tasks (e.g. work, hobbies, personal care).
–> Results in lowered activity levels and unwillingness to carry out goal-directed behaviours.
Co-Morbidity
The extent to which two or more conditions occur together.
Symptom Overlap
The extent to which the symptoms of one disorder are also present in a different disorder.
E.g. SZ and bipolar disorder both include symptoms such as delusions and avolition.
Limitation of Diagnosis
LOW VALIDITY - CO-MORBIDITY
1) If conditions often co-occur then they might be a single condition. SZ is commonly diagnosed with other conditions.
2) E.g. Buckley et al. (2009) concluded that SZ is co-morbid with depression, substance
abuse or OCD.
–> Questions the ability to tell the difference between the two conditions and diagnose accurately.
Limitation of Diagnosis
LOW VALIDITY - SYMPTOM OVERLAP
1) There is overlap between the symptoms of SZ and other conditions e.g. both SZ and bipolar disorder involve delusions and avolition.
2) Under ICD, a patient might be diagnosed with SZ; while under DSM, they might be classified with bipolar disorder.
—> This means that SZ may not exist as a condition and, if it does, it is hard to diagnose.
Limitation of Diagnosis
LOW RELIABILITY
1) Cheniaux et al. (2009) investigated the reliability of schizophrenia diagnosis.
2) 100 patients were diagnosed by different psychiatrists using both ICD and DSM criteria.
3) Results showed poor reliability.
One psychiatrist diagnosed 26 patients according to DSM and 44 according to ICD, while another psychiatrist diagnosed 13 (DSM) and 24 (ICD).
–> This means that SZ is either over- or under-diagnosed, suggesting that criterion validity is low.
Limitation of Diagnosis
GENDER BIAS
1) Men are diagnosed with SZ more often than women.
2) This could be because men are more genetically vulnerable, or women have better social support, masking symptoms.
—> Some women with SZ aren’t diagnosed so miss out on helpful treatment.
CULTURE BIAS
1) Some symptoms e.g. hearing voices, are accepted in some cultures, e.g. in Afro- Caribbean societies they ‘hear voices’ from ancestors.
Rosenhan (1973)
Study on Pseudopatients
1) 8 pseudopatients reported the same symptom, ‘I hear a voice saying thud, empty or hollow’.
2) Pps kept written records of how the ward operated, as well as how they personally were treated.
3) All were admitted and all except one. Visitors to the pseudo patients observed “no serious behavioural consequences”.
4) Many of the other patients suspected their sanity.
5) Demonstrates both the limitations of classification and the appalling conditions in many psychiatric hospitals.
Evaluation of Rosenhan
STRENGTHS:
1) Ecologically valid - field experiment.
2) Objective evidence from pseudo patients.
3) Quantitative and qualitative data.
4) Practical applications - improves diagnosis & ward conditions.
LIMITATIONS:
1) Ethics
