Classification of schizophrenia

What is the definition of schizophrenia?

A severe mental disorder where contact with reality & insight are impaired (example of psychosis)

What are positive symptoms of schizophrenia?

Atypical symptoms experienced in addition to normal experiences (e.g. hallucinations & delusions)

What are negative symptoms of schizophrenia?

Atypical experiences that represent the loss of usual experiences (e.g. avolition, anhedonia & alogia)

What are the two major systems for the classification of mental disorder?

• ICD-11: World Health Organisation’s International Classification of Disease edition 11

• DSM-5: American Psychiatric Association’s Diagnostic and Statistical Manual edition 5

How do the DSM-5 & ICD-11 differ in their classification of schizophrenia?

• In the DSM-5, one positive symptom must be present for diagnosis

• Whereas, two or more negative symptoms are sufficient under ICD-11

What is the definition of hallucinations?

Sensory experiences of stimuli that either have no basis in reality or are distorted perceptions of things that are there → positive symptom

What is an example of a hallucination?

Seeing distortions in objects that look like faces or hearing critical voices

What is the definition of delusions?

Positive symptom: irrational beliefs about themselves or the world

What is are two examples of delusions?

• Persecutory delusions: a false belief that others are trying to harm, watch or conspire against the person

• Delusions of grandeur: a false belief of having exceptional power, importance, wealth or special abilities

What is the definition of speech poverty (alogia) ?

Negative symptom: involves reduced frequency & quality of speech

What is the definition of avolition?

Negative symptom:

• a loss of motivation, leading to a lack of purposeful, willed behaviour

• results in no energy, sociability affection or attempt at personal hygiene

What is the definition of disorganised thinking?

Positive symptom:

• incoherent & jumbled thoughts that make it difficult to communicate logically → manifests as speech that switches topics abruptly/fails to stay on point or is irrelevant

What is the definition of affective flattening?

Negative symptom: reduction in the range & intensity of emotional expression (e.g. facial expression, voice tone, eye contact & body language)

What is the definition of social/occupational dysfunction?

Negative symptom: functioning in key areas (e.g. work, relationships & self-care) has significantly declined since the disturbance began

What is the definition of catatonic behaviour?

A lack of movement or abnormal movement, & a lack of responsiveness to the environment → negative symptom

What is the definition of anhedonia?

A loss of interest or pleasure in almost all activities, or lack of reactivity to normally pleasurable stimuli → negative symptom

What is the definition of reliability in relation to schizophrenia?

The diagnosis of schizophrenia must be repeatable (the results must be consistent using the same measuring tool)

What is the definition of inter-rater reliability in relation to schizophrenia?

The extent to which different clinicians reach the same conclusion

What is the difference between reliability & validity?

• Reliability: the consistency of diagnosis

• Validity: the accuracy of diagnosis

What is the definition of test-retest reliability in relation to schizophrenia?

Clinicians reaching the same conclusions at two different points in time

What is the definition of validity in relation to schizophrenia?

• The extent that a diagnosis represents something that is real & distinct from other disorders (accuracy)

• The extent that a classification system measures what it claims to measure

What is the definition of predictive validity?

Assesses how well a diagnosis can predict a person's future functioning, symptoms or outcomes

What is the definition of co-morbidity?

The occurrence of two or more disorders/conditions together (e.g. schizophrenia is often diagnosed with depression)

What problem does co-morbidity raise with schizophrenia?

It complicates treatment plans & the original diagnosis of schizophrenia may be an error if the disorders share symptoms

What is the definition of symptom overlap?

Occurs when two or more conditions share symptoms (e.g. both schizophrenia & bipolar disorder share delusions & avolition)

Discuss issues of reliability and validity associated with the classification and/or diagnosis of schizophrenia (16 marks)

Write your AO1 paragraph

• Schizophrenia is a severe mental disorder where contact with reality & insight are impaired (a form of psychosis). It is characterised by positive & negative symptoms. Positive symptoms are additional experiences beyond normal functioning (e.g. hallucinations & delusions). Negative symptoms involve the loss of normal abilities (e.g. avolition & speech poverty).

• The two main diagnostic systems are the DSM-5 (published by the American Psychiatric Association) & the ICD-11 (published by the World Health Organisation). They differ slightly in their classification of schizophrenia: the DSM-5 requires at least one positive symptom for diagnosis, whereas the ICD-11 allows a diagnosis based on two or more negative symptoms.

• Reliability refers to the consistency of diagnosis, including agreement between clinicians (inter-rater reliability) & consistency over time (test-retest reliability). Validity refers to whether schizophrenia is a distinct & genuine disorder & whether the diagnosis accurately reflects a patient's symptoms.

Discuss issues of reliability and validity associated with the classification and/or diagnosis of schizophrenia (16 marks)

Write your strength AO3 PEEL (Osorio)

• Point: One strength of schizophrenia diagnosis is there is research evidence to show that reliability can be high when standardised diagnostic criteria are used.

• Evidence: For example, Osorio reported excellent reliability in 180 schizophrenic individuals using DSM-5. Results found pairs of interviewers achieved an inter-rater reliability of +0.97 & a test-retest reliability of +0.92.

• Explain: This suggests that different clinicians are able to consistently reach the same diagnosis when using DSM-5 criteria.

• Link: Overall, this high level of reliability increases the confidence in the diagnosis of schizophrenia & supports the use of DSM-5 in clinical practice.

Discuss issues of reliability and validity associated with the classification and/or diagnosis of schizophrenia (16 marks)

Write your limitation AO3 PEEL (Rosenhan)

• Point: One limitation of schizophrenia diagnosis is that it may lack validity, meaning it does not always accurately distinguish between those with & without the disorder.

• Evidence: For example, in Rosenhan’s study, pseudo-patients presented themselves to US psychiatric hospitals claiming to hear a single unfamiliar voice, despite having no genuine symptoms.

• Explain: Results found that all patients were diagnosed with schizophrenia & admitted, even though they were mentally & psychologically healthy.

• Link: Therefore, this suggests that diagnostic criteria may lead to false positives, as some people may be wrongly classified, leading to stigma & inappropriate treatment.

Discuss issues of reliability and validity associated with the classification and/or diagnosis of schizophrenia (16 marks)

Write your limitation AO3 PEEL (Loring & Powell)

• Point: One limitation of schizophrenia diagnosis is that there is research evidence to show it may suffer from gender & cultural bias.

• Evidence: For example, Loring & Powell asked 290 psychiatrists to assess two identical case studies, with only the patient’s race & gender being varied.

• Explain: Results found that black patients were significantly more likely to be diagnosed with schizophrenia, whereas female patients were underdiagnosed.

• Link: Therefore, this suggests that diagnosis may be influenced by clinicians’ biases rather than objective assessment, reducing the accuracy of classification.