Schizophrenia
Paper 3 - Section C
,Classification / Diagnosis
Discuss reliability/validity in relation to the diagnosis and classification of SZ (16)
Discuss culture / gender bias in the diagnosis and classification of schizophrenia
Discuss issues associated with the classification diagnosis of SZ (16)
Para 1 → Outline: classification and diagnosis (AO1)
● SZ is classified as a psychotic disorder (others are mood, eating and anxiety…)
● Psychosis is broadly defined as a loss of contact with reality
● Clinicians match p’s symptoms to clinical characteristics in the classification system
● This produces a diagnosis
● Characteristics positive (delusions, hallucinations…) or negative (speech poverty…)
Para 2 → Weakness: reliability - difference in classification (AO3)
● Diagnostic reliability - diagnosis of SZ must be repeatable (different times/clinician)
● Issue as there is no agreed system of classification (DSM-V and ICD-10)
● E.g DSM requires symptoms to be present for 6 months, ICD present for 1 month
● Same person receives a different diagnosis depending on criteria/clinician used
● Diagnosed when shouldn’t / NOT when should (Implications for treatment)
● Implications for validity of diagnosis, whether they received the correct diagnosis
Para 3 → Weakness: evidence - Cooper (AO3)
● 250 p’s were considered by American AND British psychiatrists separately
● 163 diagnosed as SZ by the American psychiatrists (using DSM)
● 85 diagnosed as SZ by the British psychiatrists (using ICD)
● Suggested American psychiatrists were almost 2x as likely to diagnose SZ
● Suggested: difference in diagnostic rates wasn’t due to different incident rates (not
that more in the USA have SZ) because...... They used the SAME patients
● Therefore it must be due to the differences in the definition of SZ
Para 4 → Weakness: validity - system overlap (AO3)
● SZ is hard to diagnose accurately, people are misdiagnosed or go undiagnosed
● Symptom overlap - some SZ symptoms are present in other disorders
● Can lead to misdiagnosis / symptoms confused with other disorders
● SZ overlaps with bipolar: psychotic thinking, hostility, impulsivity, suicidal thoughts
● P’s may be incorrectly diagnosed with BPD (receive the wrong treatment)
● SZ not diagnosed accurately - difficult to understand causes of and risk factors
Para 5 → Weakness: validity - comorbidity(AO3)
● Comorbidity - p’s diagnosed with more than one disorder at the same time
● SZ often diagnosed alongside depression/substance abuse (supposedly separate
disorders)
● Evidence → Buckley concluded around ½ of p’s with SZ diagnosis also have a
diagnosis of depression (50%) / substance abuse (47%) → PTSD (29%) /OCD (23%)
● Both fairly uncommon (1% of population develop SZ / 2-3% develop OCD) we would
expect very few people with SZ to have OCD (vice versa)
● Have to decide which disorder to treat - treatments may interfere / affect recovery
● Difficult to identify characteristics specific to SZ / predict cause / outcome of SZ
● Substance abuse may be a cause of SZ / developed to cope with SZ
,Culture / gender bias
Weakness: culture bias (AO3)
● African Americans are more likely than white people to be diagnosed with SZ
● Fearon → Found a ninefold higher risk of SZ in UK- resident black Caribbeans
● Keith → 2.1% of African Americans diagnosed with SZ, only 1.4% of White Americans
● McGovern + Cope (UK) → ⅔ of psychotic p’s held in hospitals were Afro-Caribbean
● Suggestion is that the high incidence rates are due to a genetic vulnerability
● But rates in Africa / West indies not particularly high - suggests not due to genetics
Weakness: misdiagnosis due to clinician (AO3)
● Psychiatrists misinterpret symptoms / overdiagnose SZ
● Subjectivity in diagnosis psychiatrists may use cultural stereotypes
● Ethnocentrism → evaluating other groups standards / customs of one’s own culture
● Clinicians interpret behaviour in some cultures using western diagnostic symptoms
● Cultural relativism → behaviour can’t be judged properly unless it is viewed in the
context of the culture in which it originates
● E.g ‘hearing voices,’ is a main symptoms of SZ, but common in some cultures
● Validity of diagnosis is poor, either it’s confounded by cultural beliefs / behaviours in
p’s, or by a racist distrust of black patients on the part of mental health practitioners
Weakness: gender bias (AO3)
● Since 1980s men have been diagnosed with SZ more often than women
● Gender bias in diagnosis is said to occur when accuracy of diagnosis is dependent
on the gender of an individual
● Accuracy of diagnostic judgement varies due to gender-biassed diagnostic criteria
● Or clinician basing judgements on stereotypical beliefs about gender
Weakness: evidence (AO3)
● Loring / Powell - 290 M/ F psychiatrists to read 2 brief descriptions of p’s behaviour
● P’s described as ‘males’ (or no info given), 56% of psychiatrists gave a SZ diagnosis
● P’s described as ‘female,’ only 20% were given a SZ diagnosis
● Gender bias not as evident among F psychiatrists
● Suggests diagnosis is influenced by gender p’s / gender of clinician
Weakness: reasoning for lower rates in women (AO3)
● Cotton suggests women have higher interpersonal functioning
● Women’s better interpersonal functioning may bias psychiatrists to
underdiagnosed because:
● Symptoms are masked / seem too mild for diagnosis
● Women under-diagnosed, suggests diagnostic validity is poor (works on 1 gender)
, Biological explanations
Discuss biological explanations for SZ (16) Refer to evidence (16)
Para 1 → Outline: genetics (AO1)
● Evidence SZ runs in families
● Concordance: likelihood 2 ppl w/ shared genes develop same disorder
● Gottesman found concordance rate for MZ twins was 48% DZ twins was 17%
● Suggests if 1 twin is SZ, there’s a 48% chance the other twin will be too
● As genetic similarity increases so do chances of developing SZ - definite genetic link
Para 2 → Weakness: other explanations (AO3)
● Concordance wasn’t 100% - must be other factors causing SZ
● Creates a problem of nature vs nurture / brings into account diathesis stress test
● Could be, the gene puts you at risk of developing SZ / predisposed
● When exposed to life events / stressors SZ is triggered
● Suggests genetic can’t give a full explanation
Para 3 → Weakness: candidate genes (AO3)
● Individual genes have weak / inconsistent associations with SZ
● SZ is polygenic (requires many genes to work in combination)
● Research found >108 genetic regions contribute to SZ, 83 not previously identified
● One was the gene encoding the dopamine receptor DRD2,
● (target of drugs treating SZ / supports role of dopamine in SZ cause / development)
● Single gene not found responsible - a combination of genes make you vulnerable
● Only when vulnerable exposed to stressors, SZ symptoms develop - N vs N
Para 4 → Outline: dopamine Hypothesis (AO1)
● NT that helps control the brain's reward / pleasure centre
● SZ is caused by excess dopamine activity (Hyperdopaminergia) at synaptic sites
● High dopamine = + symptoms: delusions, hallucinations, confused thinking
● Evidence to support the DH comes from drugs
● Increase dopaminergic activity (Amphetamines) release dopamine at central
synapses, trigger SZ-like symptoms / worse for those already diagnosed SZ
● Decrease dopaminergic activity (clozapine/neuroleptic drugs) work by blocking
dopamine, helping reduce symptoms
Para 5 → Strengths: evidence (AO3)
● Support from drugs that increase/decrease dopamine shows it is linked to SZ
● BUT creates issue if dopamine causes SZ / SZ causes high dopamine
● Must be careful when establishing cause and effect relationships in SZ p’s
Para 6 → Weakness: limitations of TDH (AO3)
● Problems with the drugs used
● Amphetamines don’t trigger SZ in all, excess dopamine may be issue for vulnerable
● People who haven’t taken amphetamines still develop SZ
● Shows dopamine can’t be the only explanation for developing SZ
● Antipsychotics not effective for all p’s → increased dopamine can’t be the only cause
Other NTS (glutamate) also been linked to SZ
● Dopamine doesn’t provide a complete explanation for SZ