AQA Psychology - Schizophrenia


9.1 Classification of schizophrenia

Scizophrenia: type of psychosis charactersed by a disruption of cognition and emotion. 

Diagnosing schizophrenia: clinician would use a diagnostic manual, Diagnostic and Statisical Managment of Psychitric Disorders (DSM) in the US, International Classification of Diseases (ICD) in Europe. 

Positive symptoms: reflect an excess or distortion to normal funtions. Hallucinations - bizarre, unreal perceptions of the enviornment. Delusions - bizarre beliefs that seem real to person. Disorganised speech - result of abnormal though processes when individual has problem organising thoughts and it shows in their speech. Grossly disorganised of catatonic behaviour - includes inability or motivation to initiate task, leading to difficulties in daily living, characterised bby reduced reaction to immediate environment, rigid postures and aimless motor activity. 

Negative symtoms: reflect reduction or loss of normal functions, still persist when positive symptoms don't. Speech poverty(alogia) - lessening of speech fluency and productivity, which reflectis slowing or blocked thoughts. Avoliton - reduction, difficulty ot inability to initiate and persist in goal-directed behaviour, often mistaken for apparent disinterest. Affective flattening - reduction in range and intensity of expressed emotion including facial expression, voice tone, eye contact and body language. Anhedonia - loss of interest or pleasure in all or almost all activies, or lack of reacitivty to stimuli. 

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9.2 Reliability and validity in diagnosis and clas

Reliability: dianosis must be repeatable either via test-retest reliability or inter-rater reliability, inter-rater uses a kappa score 0.7 or above is considered good. Cultural differences: Copeland (1971) gave US and British psychiartrists a patient description. 69% of US diagnosed as schizophrenic but only 2% of British did. Lurmann et al. (2015) interviewed schizophrencis from Ghana, India and US, Ghana and India reported positive experiences no American's had positive experiences. 

Validity: Gender bias in diagnosis - Boverman et al. (1970) found clinicans in US eqauted mentally healthy 'adult' behaviour with mentally healthy 'males', therefore tendency or women to percieved as less mentally healthy. Symptom overlap - overlap with depression and bipolar. Ellason & Ross (1995) found those diagnosed with DID had more schizophrenics symptoms than schizophrenics. Co-morbidity - Buckley et al. (2009) found co-mordity with schizophrenia and depression in 50% of patients and 47% co-morbidity of substance abuse. Swets et al. (2014) found 12% of schizophrencis have OCD. 

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9.3 Biological explanations for schizophrenia - A0

Genetic factors: Family studies - Gottesman found cocordance rate of 46% if child has two schizophrenic parents and 13% with one, and siblings had (%. Twin studies - cocordance rates of 40.4% or MZ twins and 7.4% with DZ. Adoption studies - Tiernari et al. (2000) 6.7% of adoptees with schizophrenic mothers got schizophrenia versus 2% of those without. 

The dopamine hypothesis: high numbers of D2 receptors. Drugs that increase dopaminergic activity - amphetamine causes positive symptoms. Drugs that decrease dopaminergic activity - antipsychotic drugs increase negative symptoms.

Revised dopamine hypothesis: Davis & Kahn (1991) proposed positive symptoms caused by excess of dopamine in subcortical areas, negative arise from lack of dopamine in prefrontal cortex. Neural imaging - Patel et al. (2010) found lower levels of dopamine in schizophrenics in prefrontal cortex, using PET scans. Animal studies - Wang & Deutch (2008) induced dopamine depletion in prefront cortex in rats, resulting in cognitive impairment, they reversed this with atypical drugs, benefiting negative symptoms. 

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9.4 Psychological explanations of schizophrenia -

Family dysfunction: Double-blind theory - Gregory Bateson et al. (1956) suggested children who recieve contradictory messsages from parents are likely to develop schizphrenia, they cause a distorted version of reality, developing into symptoms, Expressed emotion - leads to stress beyond individuals coping mechanisms, triggering schizophrenic episodes, in contract supporting family may reduce episodes and dependence on medication. 

Cognitive explanations: Delusions - critical characterisitics is perception of self-involvement in events, therefore jumps to conclusions , muffled voices interpretted as god, unable consider the idea that they're wrong, inabiltiy to recognise cognitive distortions and substitute more realistics explanations for events. Hallucinations - higher expectency for occurance of voices, find it difficult to distinguish between imagenary and reality, imagination overrides senses, they don't reality check. 

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9.5 Drug therapy - A01

Antipsychotics: Typical - such as chlopromazine, primarly to combat positive symptoms, such as hallucinations, products of overactive dopamine system. Dopamine antagonists that bind dopamine receptors, D2 receptors.  ATypical - such as clozapine, combat poositive and negative symptoms. Lower risks of side effects, beneficial for negative symptoms and suitable for treatment-resistment patients. 

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9.6 Cognitive behavioural therapy - A01

CBTp phases: Assessment, Engagment, ABC model, Normalisation, Critical collaborative analysis and developing alternative explanations. 

CBTp: used to correct interpretations of patients, usually one-to-one, NICE recommended 16 sessions, finding alternative explanations of why they feel how they do reduces stress and improves functioning.

Nature of CBTp: trace back to origins to find development, set behavioural assigments, learning of maladaptive responses. 

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9.7 Family therapy - A01

Family therapy: interventions aimed at family of schizophrenic, interventions should be priority when persistent symptoms of high chance of relapse, high expressed emotion families have more relapses. Nature of family therapy - period of 3 to 12 months, 10 or more sessions, aimed at reducing expressed emotion, Garety et al. (2008) claimed relapsed rates 25% with those with family therapy versus 50% of those without. 

Pharoah et al. (2010): Procedure - reviewed 53 studies between 2002 and 2010 to investigate family therapy, studies in Europe, Asia and North America, compared to 'standard' care. Concentrates on randomised controlled studies (RCTs). Findings - some showed improvment in mental state and some didn't, increased patients' compliance with medication, didn't improve living independently or employment, reduction in risk of relapse and hospital admission for 24 months. 

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9.8 Token economy and the effect of schizophrenia

The token economy: set target behaviours that are rewarded with tokens and tokens buy rewards, aims at increasing occurance of target behaviour. Assigning value to the tokens - token needs to be assosiated with stimulus, through classical conditionng, tokens becomes secondary reinforcers and used to modify behaviour. Reinforcing target behaviour - the more items/rewards the token is assosiated with the more powerful the token becomes. The 'trade' - during early stages of token economy frequent exchanges mean patients quickly reinforced abd target behaviours can increase in frequency, the more that time passes between token and exchange the less the inforcement. 

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9.9 An Interactionist approach - A01

Diathesis-stress model: Diathesis - schizophrenia has genetic component, greater risk of cocordance the closer the family, as twins have cocordance rate of 50% there's indication that enviornment has affect of development. Stress - childhood trauma/stresses from unbanised environment, Varese et al. (2012) found 3 times the risk of schizophrenia is individual experienced trauma before 16 years, Vassos et al. (2012) found urban areas have 2.37 higher chance of devlopment verus rural. Addidtive nature of diathesis and stress - diathesis plus stress develop the disorder. 

Tiernari et al. (2004): Procedure - 145 adoptees with high risk, and 158 without genetic risk, assessed family function using OPAS. Findings - 14/303 developed schizophrenia 11 were high risk group, high risk had adoptive-family stress as a predictor of devlopment of schizophrenia. 

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