Diagnosis & Classification Flashcards
What is schizophrenia?
a severe mental illness where contact with reality and insight are impaired
DSM5
one positive symptom must be present for at least 6 months
ICD10
2+ negative symptoms
What are positive symptoms?
atypical symptoms experienced in addition to normal experiences - hallucinations and delusions
What are hallucinations?
Sensory experiences of stimuli that have no basis in reality, or are distorted perceptions of things that are e.g. auditory: hearing things that are not really there
What are delusions?
beliefs that have no basis in reality e.g. grandeur (importance e.g. God), paranoia, persecution, control (external)
What are negative symptoms?
atypical experiences that represent the loss of usual experience e.g. thinking normal levels of motivation - avolition, speech poverty
What is avolition?
loss of motivation to carry out tasks e.g. work, and results in lowered activity levels
What is speech poverty?
reduced frequency/quality of speech
What is comorbidity?
the occurrence of two illnesses/conditions together - calls us to question the validity of classifying the two separately
AO3 of comorbidity
Buckley: 50% depression and scz
47% scz and substance abuse
- one single condition?
- separate conditions with symptoms of both?
What is symptom overlap?
2+ conditions share symptoms - questions validity of classifying the two separately
AO3 symptom overlap
Ketter: misdiagnosis due to symptom overlap can lead to years of delay in recovery which results in further degeneration and increased suicide rates
What is the validity referring to?
whether the classification system measures what it aims to
What is the predictive validity?
how similar individuals diagnosed are
What is aetiological validity?
how similar patients causes are
What is raw predictive validity?
how useful diagnostic tools are for predicting the right treatment
What is the construct validity?
shared common features of patients
AO3 validity for schizophrenia
- no single symptom (doubt construct validity) and diagnosis is subjective
- same treatment may have different outcomes (Birchwood and Jackson: 20% recover, 10% suicide)
- more likely diagnosed with ICD than DSM
What is the reliability referring to?
how far the classification system produces same diagnosis for a particular set of symptoms - different clinicians should meet the same diagnosis
AO3 for reliability
Beck: 4 psychiatrists agree how to use DSM for 153 patients - only 54% agreement due to: different information given by patients, different judgement, mostly inadequacies in classification system
Soderberg: 81% concordance rate using a later DSM
Gender bias in diagnosis
Longenecker: more men diagnosed since 80s, thought because women tend to function better, so are less likely to be diagnosed - problem as the same symptoms give different diagnosis
Culture bias in diagnosis
rates of diagnosis vary among ethnic groups, African Americans more likely to be diagnosed than white Americans with similar symptoms. Admit hallucinations more easily for example. Stress possibly due to racism, higher chance of poverty
