Classification + Diagnosis Flashcards
Positive symptoms
Those that appear to reflect an excess or distortion of normal functions
Delusions
Experiences of control
Hallucinations
Disordered thinking
Negative symptoms
Those that appear to reflect a diminution or loss of normal of normal functions
Affective flattening
Avolition
Alogia
Delusions
Bizarre beliefs that seem real to the person with sz but are not real e.g. inflated beliefs about the person’s power
Experiences of control
Person may believe they are under control of an alien force that has invaded their mind
Hallucinations
Bizarre, unreal perceptions of the environment that are usually auditory but may also be visual, olfactory or tactile
Disordered thinking
Feeling that thoughts have been inserted or withdrawn from the mind
Person may believe their thoughts are being broadcasted, so others can hear
Affective flattening
A reduction in the range + intensity of emotional expression, e.g. facial expression, voice tone eye contact + body language
Avolition
Reduction or inability to initiate + persist in, goal-directed behaviour = often mistaken for apparent disinterest
Alogia
Poverty of speech, characterised by lessening of speech fluency + productivity
Reflects slowing or blocked thoughts
Reliability
Refers to consistency of a measuring instrument e.g. questionnaire or scale, to assess
How can reliability be measured?
In terms of whether 2 independent assessors give similar diagnoses = inter-rater reliability
Or whether tests used to deliver these diagnoses are consistent over time = test-retest reliability
Inter-rater reliability
DSM-III designed to provide a much more reliable system to classify disorders
Review: claimed DSM had fixed problem of inter-rater reliability once and for all
Now there was a reliable classification system = led to much greater agreement over who had Sz
Test-retest reliability
Cog screening tests e.g. RBANS = important for diagnosis of Sz as they measure the degree of neuropsychological impairment
Wilks et al: gave 2 alternate forms of cog test to Sz patients over intervals varying from 1-134 days
Test-retest reliability was high at .84
Validity
Refers to extent that a diagnosis represents something that is real + distinct from other disorders + the extent that classification system such as DSM measures what it claims to measure
Comorbidity
Refers to the extent that two conditions co-occur
Psychiatric comorbidities are common among p’s with Sz e.g. substance abuse, anxiety + depression
Comorbidity creates difficulties in diagnosis of a disorder + deciding what treatment to advise
Buckley et al
Estimated that comorbid depression occurs in 50% patients + 47% of patients also have lifetime diagnosis of comorbid substance abuse
Positive or negative symptoms?
Found +ve symptoms were more useful in diagnosis than -ve symptoms
Prognosis
Sz’s rarely share the same symptoms, no is there evidence that they share the same outcomes
Diagnosis had little predictive validity = some people never appear to recover but many do
Evaluation of Inter-rater reliability
Still little evidence that DSM is used with high reliability by mental health clinicians
Whaley = Inter-rater reliability correlations in sz diagnosis as low as +.11
Rosenhan
Normal people presented to psychiatric hospital in US claiming heard unfamiliar voice sating ‘empty’, ‘ hollow’ + ‘Thud’
ALL were diagnosed as Sz + admitted + staff didn’t recognise normality
Follow-up study = warned hospitals of pseudopatients = 21% detection rate despite none being there
Unreliable symptoms
Onlt 1 characteristic of Sz needed if delusions are bizarre = what is bizarre?
Asked 50 US psychiatrists = inter-reliability correlations of only +.40
Comorbidity + medical complications
Poor levels of functioning in Sz = result of untreated comorbid physical disorders than sz
P’s diagnosed with Sz also diagnosed with medical probs e.g diabetes or asthma
Consequence of being diagnosed with Sz = p’s tend of receive lower standard of medical care = adversely affects their prognosis
Suicide risk
Sz’s pose high risk for suicide, which comorbid depression being major cause
Attempted suicide rate rose from 1% for those with only Sz to 40% for those with comorbid mood disorder
Ethinicity
UK: rates of Sz = higher in African-caribbeans than white
Harrison et al = Sz incidence rate for Sz = 8 x higher for African-caribbean groups than white
Could be result of poor housing, higher rates of unemployment + social isolation
Or result of cultural factors: language + mannerisms
