Reliability and Validity of schizophrenia
Biological explanations for schizophrenia
Biological treatments for schizophrenia
Psychological explanations for schizophrenia
Psychological treatments for schizophrenia
The interactionist approach to schizophrenia
Managing Schizophrenia - Token Economies
Biological Explanations for Schizophrenia
Genetic similarities
Gotteman et al large scale family study →
Aunt 2%, sibling 9%, identical twin 48%
Share environment and genes - correlation
Candidate genes - polygenic inheritance coding for dopamine
Ripke et al - SCZ genetic makeup vs control - separate variations found
Aetiologically heterogeneous
OG hypothesis → hypERdopaminergia - high dopamine in subcortical areas (positive symptoms)
REVIVED → hypOdopaminergia - low dopamine in prefrontal cortex (negative symptoms)
Cortical hypOdopaminergia leads to supcortical hypERdopaminergia
Support → Tienari et al - adoptees in Finland w/ biological SCZ mother 6.9% chance
Hilker et al → concordance rates 33% MZ and 7% DZ - regardless of environment, genes significant
Limitation → environment significant. Morgan et al → birth complications and smoking THC cannabis in teen
years. Psychological risk e.g childhood trauma leads to vulnerability in mental health. Morkved → 67% SCZ at
least 1 childhood trauma vs 38% matched group with no psychotic issues. Genetics aren’t complete.
Support → Amphetamines increase dopamine worsening SCZ symptoms (Curran et al). Antipsychotics reduce
dopamine, reducing symptoms. Noll et al → dont work ⅓ w/ positive symptoms
Limitation → McCutcheon → post mortem showed raised glutamate levels in SCZ patients
Moghaddan and Javitt → link between glutamate and SCZ symptoms
Antipsychotics should not just focus on dopamine
Classification and Diagnosis
A01 thoughts and emotions are impaired and contact is lost with external reality. affects 1% of the population,
most common psychotic disorder, mainly men. the clinician uses a diagnostic manual for criteria fitting. American
DSM-5 (5 positive symptoms - 6 months symptoms) and European ICD-11 (2 or more symptoms - symptoms 1
month). subtypes dropped as inconsistent
A01 Positive - delusions and hallucinations
Negative - Alogia and Avolition
A03 Osorio - DSM-5 reliability 180 people. Interrater reliability +.97 and test retest +.92. Removed old criteria -
positive symptoms bizarre (subjective)
A03 Ethnocentric - cultural differences
Pinto and Jones - British African Caribbean 9x likely SCZ than British people
Luhmann interviewed 60 adults - Ghana, India, USA
Africans and Infians - positive experiences
, Us - negative experiences
Different meanings, discriminated against by cultural biassed system
A03 Gender bias
Fisher and Buchanan - men more diagnosed, ration 1.4:1
Genetically vulnerable or clinician affecting diagnosis - men overdiagnosed
Cotton et al - women closer, more support
Loosing custody
Underdiagnosis - receiving less treatment
A03 Symptom overlap - SCZ and BPD (delusions and avolition)
Ellason and Ross - DID more symptoms of SCZ than SCZ patients
Reliability and Validity of Schizophrenia
A01 Reliability - Interater - two clinicians reach the same conclusions with the same manual/criteria. Kappa score
of 1 (perfect agreement) and 0 (no agreement). 0.7 above is good. DSM-5 - Whaley - 0.11 and Reiger 0.46.
Manuals not reliable causing misdiagnosis/ missed diagnosis. Not accessing the right treatment/services. Test
retest - same conclusions reached at two different times.
A03 Osorio excellent reliability in DSM-5 for 180 individuals. Inter rater +.97 and test retest +.92. Improved
reliability by removing criteria that positive symptoms have to be ‘bizarre’ enough - subjective, disagreed
meaning.
A01 Reliability - Culture Bias - Pinto and Jones - British African Caribbean 9x likely diagnosed vs white british.
Those in their own countries aren't. Ethnocentric - not reliable as different diagnosis for different cultures, not
consistent.
A03 Luhmann interviewed 20 adults from Ghana, India and US about voices. Positive - playful, offering advice,
negative - violent and hateful. Culture impacts symptom experience. Shouldn’t be used to classify in other
cultures.
A01 Validity - Gender bias - Fisher and Buchanan - men more diagnosed 1.4:1. Cotton et al - women function
better, likely to work with good family relationships.
A03 Loring and Powell - overdiagnosis of males and underdiagnosis females - not enough service/treatment.
Gender influences diagnosis, male psychiatrist overdiagnosed men. Women don't want to lose custody.
A01 Symptom overlap - SCZ and BPD (delusions) - may not be two conditions. Hard to distinguish and diagnose.
Variations of the same condition?
A03 Ellason and Ross - DID more SCZ symptoms than SCZ patients. SCZ criteria invalid, not distinct from other
disorders, misdiagnosis likely.
Biological treatments for schizophrenia
A01 Typical antipsychotics - reduce positive symptoms
Antagonists bind to D2 - blocking neurotransmission
Kapur et al - 60-70% D2 receptors blocked - tardive dyskinesia
Chlorpromazine - initially dopamine increase then reduced production
Sedative calming - not just SCZ condition
A01 Atypical antipsychotics - reduce negative symptoms
Antagonists bind to D2 - blocking neurotransmission TEMPORARILY
Rapidly dissociate allowing normal transmission
No tardive dyskinesia
Clozapine - acts on dopamine, serotonin and glutamate receptors