Schizophrenia Flashcards
How is schizophrenia classified/diagnosed?
Schizophrenia is a collection of seeming unrelated symptoms
The DSM-5: one positive symptom must be present (delusions, hallucinations or speech disorganisation).
The ICD-10: two or more negative symptoms are sufficient for diagnosis (avolition and speech poverty)
What are positive symptoms?
Additional experiences beyond those of ordinary existence.
What are hallucinations?
Sensory experiences that have no basis in reality or distorted perceptions of real things. Experienced in relation to any sense.
For example hearing voices or seeing people who aren’t there.
What are delusions?
Beliefs that have no basis in reality - make a person Schizophrenia behave in ways that make sense to them but bizarre to others.
For example beliefs about a very important person or the victim of a conspiracy.
What are negative symptoms?
Loss of usual abilities and experiences
What is avolition?
Severe loss of motivation to carry out everyday tasks (work, hobbies, personal care).
Results in lowered activity levels and unwillingness to carry out goal-directed behaviours.
What is Speech Poverty?
A reduction in the amount and quality of speech. May include a delay in verbal responses during conversation.
DSM emphasises speech disorganisation and incoherence.
What are the key issues in diagnosis of Schizophrenia?
Reliability: the extent to which the diagnosis of schizophrenia is consistent.
Validity: the extent to which the diagnosis and classification techniques measures what they are designed to measure.
Co-morbidity: occurrence of two illnesses together which confuses diagnosis and treatment.
Symptom overlap: when two or more conditions share symptoms, questioning the validity of the classification.
What are 4 limitations in diagnosing schizophrenia?
Low reliability. One study had two psychiatrists independently diagnose 100 patients using both the DSM and the ICD. They had poor inter-rater reliability. One psychiatrist diagnosed 26 patients using the DSM and 44 with the ICD. The second diagnosed 13 using the DSM and 24 with the ICD. This inconsistency between professionals and different systems weakens the reliability.
Another limitation is validity.One way of assessing validity is to see whether both systems arrive at the same diagnosis for patients. One study shows that schizophrenia is more likely to be diagnosed using the ICD than the DSM. This suggests that either the DSM under diagnoses or the ICD over diagnoses schizophrenia - which reduces the validity of the study.
Co-morbidity-when two conditions appear together- if it happens a lot then this may call into question whether they are actually a single condition. One study concluded that half of patients with a diagnosis of schizophrenia also have a diagnosis of depression or substance abuse. In terms of classification if depression looks like schizophrenia or vice versa then they may be a single condition - which is confusing.
Gender-bias. One study concluded that since the 1980’s men have been diagnosed with schizophrenia more often than women. Cotton found that female patients also function better than men. This could explain why women are not diagnosed as often - because their interpersonal functioning may bias practitioners to under-diagnose schizophrenia. This is a limitation, as men and women with similar problems may experience differing diagnoses.
