Classification of Schizophrenia
- Created by: miss_t2000
- Created on: 05-04-19 21:11
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- Classification of Schizophrenia
- a diagnosis is made by a clinician through the use of a diagnostic manual, such as the DSM, or the ICD
- a type of psychosis in which thoughts and emotions are impaired, causing a loss of external reality
- affects around 1% of the population, commonly between 15 and 35yrs, although many live a normal life subsequently
- Positive Symptoms
- Hallucination - unreal physical perceptions
- olfactory - scents
- auditory - voices may be instructional, harmful, or narrative
- visual - seeing lights, objects or faces
- tactile - feeling physical sensations, eg bugs on the skin
- Delusions - bizarre irrational beliefs
- Delusions of Paranoia, often feeling they are at risk of harm
- Delusions of Grandeur, experiencing inflated importance or talent
- Delusions of reference, believing there are subliminal messages for them in the media
- Disorganised Speech - results from abnormal thought processes
- inability to organise thoughts is reflected i speech
- rapid meaningless progression between topics (derailment)
- may be so severe that no coherent meaning can be conveyed (word salad)
- Catatonic behaviour
- actions and movement may be grossly disorganised or catatonic in nature
- includes inability to initiate or complete a task
- results in difficulties in daily life and poor hygiene interests
- reduced reaction to immediate environment, rigid postures or aimless motor activity
- positive symptoms are in excess to normal funtion
- Hallucination - unreal physical perceptions
- Negative Symptoms
- appear to be a reduction or absence of normal function
- weaken the ability to cope with daily life but patients are unconcerned
- having enduring (1yr) negative symptoms is the Deficit Syndrome, giving people a worse prognosis
- Speech Poverty - lessening of spoken productivity
- thought to reflect slow or blacked thoughts
- may produce fewer words in a given time, struggling to produce spontaneous language
- less complex syntax
- Avolition - a reduction in interests and desires
- inability to initiate and persist in goal-orientated behaviour
- reduction in self-initiated behaviours which are readily available to individual
- Flat Affect - reduction in the range and intensity of emotion
- includes facial expression, vocal tone, eye contact and body language
- may show a deficit in prosody, and remove any indication of enthusiasm
- Anhedonia - loss of interest and pleasure in activities
- may be pervasive (all aspects of pleasure)
- physical - lack of pleasure from food, bodily contact etc
- social - lack of pleasure from interpersonal interactions
- psychical anhedonia is a greater indicator of schizophrenia as it isn't comorbid with depression
- Reliability
- diagnostic reliability means that a classification must be repeatable
- this may be reaching the same conclusion at different points in time (test-retest)
- may be reaching the same diagnosis by two clinicians (inter-rater)
- measured by the agreement kappa score
- 0.7 shows strong reliability
- schizophrenia classification is only 0.46
- measured by the agreement kappa score
- cultural differences
- culture has a great influence on the diagnosis process of schizophrenia
- Copeland (1971) found when given the same desription 69% of US diagnosed, but only 2% of UK
- cultural environments may affect the interpretation of the key characteristic (eg hearing voices)
- african and indian ppts reported positive, helpful voices
- US subjects all describes them as violent and hateful
- culture has a great influence on the diagnosis process of schizophrenia
- diagnostic reliability means that a classification must be repeatable
- validity
- gender bias
- affected by gender-based diagnostic criteria
- affected by judgements of gender stereotypes
- healthy behaviour may be equated with 'male' behaviour as the norm
- more likely to perceive women as mentally unhealthy
- symptom overlap
- positive and negative symptoms are frequently found in other disorders
- eg people with dissociative identity disorder display more schizophrenic symptoms
- most people with schizophrenia have sufficient symptoms to also be diagnosed with another disorder
- co-morbidity
- important in the validity of mental illness diagnosis
- refers to the extent to which two conditions can co-occur
- eg substance abuse, anxiety, depression
- Swets et al found OCD and schizophrenia are highly co-morbid (12%)
- gender bias
- Evaluation
- validity
- gender bias - research support
- 290 psychiatrists asked to read cases of patient behaviour
- when patient was genderless or male, 56% diagnosed as schizophrenia
- when described as female on 20% diagnosed the same patient with schizophrenia
- but gender bias is less evident amongst female psychiatrists
- consequence of co-morbidity
- psychiatric and behavioural diagnoses accounted for 45% of co-morbidity
- many patients with schizophrenia also had asthma, hypothyroidism
- suggested that a psychiatric diagnosis can limit standard of overall medical care
- difference in prognosis
- no evidence that people with schizophrenia have any common outcomes
- 20% tend to recover to previous level of functioning
- 10% have lasting and significant improvement
- 30% have improvement with intermittent relapse
- suggests a diagnosis offers little predictive validity
- gender bias - research support
- reliability
- lack of inter-rater reliability
- little evidence that DSM is used reliably by clinicians
- study has found kappa scores as low as 0.11
- unreliable symptoms
- it is only necessary that 'delusions are bizarre' for diagnosis
- little inter-rater reliability (0.4) of what actually classifies as 'bizarre' however
- suggests even central criteria lack reliability
- cultural differences
- study has established cultural and racial differences in diagnosis
- prognosis for minority groups is often better
- suggests patients experience less distress because of more supportive/ protective social support networks
- called the ethnic culture hypothesis
- lack of inter-rater reliability
- validity
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