Schizophrenia Flashcards
(45 cards)
What is schizophrenia
A severe mental disorder where contact w reality and insight are impaired
Positive symptoms
Atypical symptoms experienced in addition to normal experiences
- hallucinations and distortions
Negative symptoms
Atypical experiences represent a loss of a usual experience
- speech poverty and avolition
5 key symptoms in diagnosis of psychotic disorders
Delusions
Hallucinations
Disorganised speech
Catatonic behav
Negative symptoms
DSM 5 diagnosis criteria
2 of 5 of the key symptoms and at least one must be positive
ICD 10 diagnosis criteria
2/5 of the symptoms present both can be negative
Reliability of diagnosis
Using DSM inter rater reliability = +0.97
Test retest reliability = +0.92
We can be sure that diagnosis of Sz is not reliant on subjective clinician but the symptoms themselves
Validity of diagnosis
Cheniaux 2 psych assess same clients using both DSM and ICD
68 under ICD and 39 under DSM
Sz is either under/over diagnosed
Validity is low
Rosenhans study
Rosenhan and other participants faked auditory hallucinations to gain admission into psych hospitals
All said they were fine but we’re forced to admit had Sz
Perfectly healthy patients diagnosed shows poor validity
Biological explanations
Genetics
Neural correlates
Genetic basis for Sz concordance
Gottesman - as genetic similarity increases so does the probability of sharing Sz 48% for identical twins 17% dizyg
Candidate gene
Sz is polygenic controlled by multiple genes
Ripke studied 37000 patients with Sz compared to more than 110k controls
Found 108 separate genes were related increasing risk of sz
Aetiologically heterogeneous
Different combinations of genetic variation can lead to development of Sz
Mutation and Sz
Parental dna mutate as increased exposure to radiation
Sperm mutation - 0.7% chance child has Sz if father under 25 2% in fathers over 50 ( Brown et al)
Original dopamine hypothesis
-Dopamine has excitatory effect
-Unusually high levels associated to Sz with positive symptoms- hallucinations
-Neurones fire too easily or too often
-Sz thought to have abnormally high levels of D2 receptors
Updated hypothesis - Davis et al
High levels of dopamine not found in all Sz
Modern drug clozapine very little blocking still works
Could be due to both too high dopamine and too low
Hypodopaminergia
Too low dopamine - negative symptoms
Prefrontal cortex responsible for thinking
Hyperdopaminergia
Too high dopamine production
Poverty of speech or auditory hallucinations
Subcortical areas - Broca’s area
Family dysfunction
A family that fails to provide for and meet the needs of one or all of its members. Typically characteristics are poor communication and cold parenting - develop Sz
Schizophrenogenic mother
-Causes disorder by being cold and distant but controlling and dominant
-Child show emotion towards her but is also punished creates a tense atmosphere - explain distrust and paranoid delusions
Double bind theory
Bateson - child think they’re doing wrong but receive mixed messages what the wrong thing is
Unable to comment on the unfairness
When wrong punished removal of love
Cause disorganised thinking and paranoid delusions
Expressed emotion
Focus on relapse rather than cause
- hostility- parent hostile including anger rejection and blame
- emotional over involvement - needless self sacrifice and overprotective
- verbal criticism - name calling threats and violence
Cognitive explanation
Focus on the role of mental processes
Brain areas / structures when not working properly seem to affect thought processes
Ventral striatum
Deals with dopaminergic neurones signals cause expectation of reward
When Sz scan show reduce firing - avolition (lack motivation)
