Classification and Diagnosis Flashcards
Positive symptom
reflect an excess of normal functions
Negative symptom
reflect a loss of normal functions
Delusion
bizarre beliefs, seem real can be paranoid in nature. delusion of grandeur/ persecution
Experiences of control
under control of external force that has invaded mind
Hallucinations
bizarre, unreal perceptions of environment
Disordered thinking
thoughts inserted/ withdrawn from mind
Affective flattening
reduction in range and intensity of emotional expression
Alogia
poverty of speech
Avolition
inability to initiate in goal-directed behaviour
Validity
extent diagnosis represent something distinct from other disorders and ICD/DSM measures what it claims to
Reliability
consistency of diagnosis
Inter-rater reliability - DSM-III (1980)
designed to be more reliable
Carson (1991): claimed it fixed the problem, should lead to greater agreement
Test-retest reliability - Wilks et al. (2003):
2 forms of cognitive screening tests given to patients over varying intervals, 1-134 days
correlation of scores across 2 test periods was .84
Co-morbidity
extent 2+ conditions co-occur
Co-morbidity - Buckley et al. (2009)
estimate depression occurs in 50% of patients
47% have lifetime diagnosis of co-morbid substance abuse
difficulties in diagnosis and treatment
Validity - Positive or negative symptoms?
assessed 489 admissions to psychiatric unit in Germany
found positive symptoms more useful for diagnosis then negative
Prognosis
diagnosed, rarely share symptoms, no evidence of same outcomes
varies: 20% recover previous level functioning, 10% achieve significant and lasting improvement, 30% improve with intermittent relapses
little predictive validity
Inter-rater reliability - little evidence
that DSM is used with high reliability
correlations in diagnosis .11
Unreliable symptoms - US
50 psychiatrists, differentiate non- and bizarre
inter-rater reliability correlation .40
diagnosis based on ‘bizarre’ delusions not reliable method of distinguishing( non-)schizophrenic patients
Comparing DSM and ICD
Cheniaux et al. (2009): inter-rater relaibility above .50
SZ more frequently diagnosed according to ICD-10
Cultural differences - Copeland (1971)
US and British psychiatrist given patient description
69% US diagnosed SZ, 2% British
Co-morbidity and medical complications
Weber et al. (2009): evidence of co-morbid physical disorder (e.g. diabetes, asthma)
if untreated, poorer prognosis
Co-morbidity and suicide risk
attempted suicide rose from 1% to 40% for those with at least 1 co-morbid mood disorder
Symptoms - DID
symptoms found in mood disorders
Ellason and Ross: people with dissociative identity disorder have more symptoms of SZ
