Schizophrenia - Diagnosis/Classification Flashcards
What is schizophrenia?
Schizophrenia is a severe mental disorder where contact with reality and insight is impaired, also experienced by about 1% of the population. It is more commonly diagnosed in men than women, more commonly diagnosed in cities than the countryside, and in working-class rather than middle-class people.
What are the two major systems for the classification of schizophrenia?
The two major systems are the International Classification of Disease (ICD-10) and the American Psychiatric Association’s Diagnostic and Statistical Manual edition 5 (DSM-5).
In the DSM-5 system, one of the so-called positive symptoms (delusions, hallucinations, or speech disorganisation) must be present for diagnosis.
ICD-10 recognises a range of subtypes of schizophrenia:
Paranoid schizophrenia is characterised by powerful delusions and hallucinations but relatively few other symptoms.
Hebephrenic schizophrenia is characterised mainly by negative symptoms.
Catatonic schizophrenia is disturbance to movement, leaving the person immobile or overactive.
What are positive symptoms of schizophrenia?
Positive symptoms of schizophrenia are atypical symptoms experienced in addition to normal experiences. They include hallucinations and delusions.
What are hallucinations?
Hallucinations are a positive symptom of schizophrenia. They are sensory experiences of stimuli that have either no basis in reality or are distorted perceptions of things that are there.
What are delusions?
Delusions are a positive symptom of schizophrenia. They involve beliefs that have no basis in reality, for example, that the person with schizophrenia is someone else or that they are the victim of a conspiracy.
What are negative symptoms of schizophrenia?
Negative symptoms of schizophrenia are atypical experiences that represent the loss of a usual experience such as clear thinking or ‘normal’ levels of motivation.
What is speech poverty?
Speech poverty is a negative symptom of schizophrenia. It involves reduced frequency and quality of speech.
What is avolition?
Avolition is a negative symptom of schizophrenia. It involves loss of motivation to carry out tasks and results in lowered activity levels.
What is one evaluation point about reliability?
Reliability: Reliability means consistency. An important measure of reliability is inter-rater reliability, the extent to which two or more mental health professionals arrive at the same diagnosis for the same individual. Elise Cheniaux et al. (2009) had two psychiatrists independently diagnose 100 people using both DSM and ICD criteria. Inter-rater reliability was poor, with one psychiatrist diagnosing 26 with schizophrenia according to DSM and 44 according to ICD, and the other diagnosing 13 according to DSM and 24 according to ICD. This poor reliability is a weakness of diagnosis of schizophrenia.
What is one evaluation point about validity?
Validity: Validity is the extent to which we are measuring what we are intending to measure. In the case of a mental disorder like schizophrenia, there are a number of validity issues to consider. One standard way to assess validity of a diagnosis is criterion validity—do different assessment systems arrive at the same diagnosis for the same person? Looking at the figures in the Cheniaux et al. study above we can see that schizophrenia is much more likely to be diagnosed using ICD than DSM. This suggests that schizophrenia is either over-diagnosed in ICD or under-diagnosed in DSM. Either way, this is poor validity – a weakness of diagnosis.
What is one evaluation point about co-morbidity?
Co-morbidity: Co-morbidity refers to the occurrence of two disorders or conditions together, for example, a person has both schizophrenia and a personality disorder. If conditions occur together a lot of the time then this calls into question the validity of their classification because they might actually be a single condition. Peter Buckley et al. (2009) concluded that around half of people with a diagnosis of schizophrenia also have a diagnosis of depression (50%) or substance abuse (47%). Post-traumatic stress disorder also occurred in 29% of cases and OCD in 23%. If half the diagnosis of schizophrenia are also diagnosed with depression, maybe we are just quite bad at telling the difference between the two conditions.
What is one evaluation point about symptom overlap?
Symptom overlap: There is considerable overlap between the symptoms of schizophrenia and other conditions. For example, both schizophrenia and bipolar disorder involve positive symptoms like delusions and negative symptoms like avolition. This questions the validity of the classification and diagnosis of schizophrenia. Under ICD a person might be diagnosed with schizophrenia; however, many of the same individuals would receive a diagnosis of bipolar disorder according to DSM criteria.
