Schizophenia

View mindmap
  • Schizophrenia
    • Biological explanantions
      • Genetic Factors- Gottesman did a large scale family study- identical twins had 48% risk of developing SZ, as the percentage of shared genes drops so does risk of developpping SZ.
        • Adoption studies by Tienari er al show that children of SZ sufferes are still at heightened risk if adopted into families with no history of SZ - genetics more important than environment
        • Twin studies dont have 100% concordance - must be other factors
        • Candidate genes - Ripke et al carried out meta-analysis comparing all data from genome-wide studies. 108 seperate genetic variations were associated with increased risk of SZ. including genes coded for the function of neurotransmitters.-polygenic and aetiologically heterogeneos
      • Neurochemical - dopamine hypothesis
        • Hyperdopaminergia- high levels of activity of dopamine in the subcortex. An excess of dopamine receptors in Broca's area may lead to speech poverty.
        • hypodopaminerergia - Golmain-Rakic et al found a role for low levels of dopaminein prefrontal cortex which is responsible for thinking and decision making - lead to  negative symptoms
        • unclear if increased receptors in post-mortem studie is cause of SZ or the result oof the drugs that have been taken.               Pearlson et al used PET scans and showed a substantial increase in dopamine receptors in patients with SZ- supports dopamine hypothesis.
      • Neural correlates- measurement of the structure or function of the brain that correlate with an experience.
        • Positive symptoms - Allen et al scanned the brains of patients experiencing auditory hallucinations. lowe activation levels in the superior temperol gyrus and anterior cingulate gyrus.
        • Negative symptoms - Juckel et al measured activity levels in ventrial striatum and found lower levels of activity compared to cintrols
        • Big problems with establishing cause and effect.                Lewis concluded a meta-analysis and found no significant link between enlarged ventricles and negative symptoms -  no correlation
    • Classification of SZ
      • a pyschotic disorder whereby individuals fail to distinguish between reality and fantasy.
      • DSM-V - American psychiatric association diagnostic and statistical classification system
        • must show one of each type of symptom
      • ICD-10 - international classification of disease
      • Positive symptoms - the presence of symptoms not normally seen in normal behaviour.
        • Delusions, Hallucinations, Disorded speech and thinking, Echolalia, Neologism, Word salad
      • Negative symptoms - the absence of symptoms seen in normal behaviour.
        • Speech poverty, Affective Flattening, Avolition
      • Issue No'1 - reliability - One issue is that it lacks inter-rater reliability. Cheniaux et al had 2 pyschiatrist independently diagnose 100 patients using both classification tecniques. one psychiatrist diagnosed 26 with DSM and and 44 according to ICD, the other diagnosed 13 with DSM and 24 according to ICD.
        • Copeland gave US and British pyschiatrist adescription of a patient.     69 % of US gave diagnosis compared to 2% of British.
        • Criterion Validity - ICD diagnosed more people. lack of validity.
      • Co-morbidity - Buckley et al concluded that around half of patients with SZ also have a diagnosis of depression or substance abuse - bad at telling difference or are they the same.
    • Psychological explanations
      • Family Dysfunction
        • Schizophrenogenic mother - Fromm-Reichmann there is a particular type of parent called the "schizophrenogenic mother". the parent is: cold, harsh, controlling, strict, rejecting towards their child and secretive. This can lead to the child becoming distrustfull of others and result in paranoid delusions and ultimately SZ.
        • Double bind theory - Bateson argued that family climate is important in the development of SZ but emphasised the role of communication style within a family. conflicting messages in family communication leads to disorganised thinking
        • Expressed emotion (EE): criticsm, hostility and over-involvement leads to relapse in patients
      • Brown split families into low EE and high EE. when SZ sufferes returned home. 10% relapse in low EE and 58%          in high.      an issue with research is that info about childhood is collected after onset of SZ so it may be distorted.          no supporting evidence fo schizophrenogenic mother or double bind - reducing validity and reliability.          it also implies that parents are to blame.
      • Cognitive explanantions - SZ is associated with several types of abnormal information processing and these can provide possible explanations.
        • Frith et al identified dysfunctional thought processing in metarepresentation as a possible explanation of hallucinations and delusions
          • metarepresentation is the cognitive ability to reflect on ones thoughts and behaviour.
        • central control is the cognitive ability to surpress automatic responsess while we perform deliberate actions. Dysfunction of this may lead to speech poverty.
        • Neufield compared the cognitive process of people with SZ with a control group. Participants with SZ took longer to encode stimuli and showed short term memory problems, suggesting their ability to process info was impaired.                          The links are clear, however we don't know anything about the origin of these cognitions or SZ
    • Biological treatments
      • Typical drug therapy- Chloropromazine - strong association between chloropromazine and dopamine hypothesis         works as antagonist and blocks dopamine receptors in the synapses in the brain, reducing the action of dopamine thus reducing symptoms like hallucinations
        • Thornley et al reviewed studies comparing chloropromazine to placebos. All studies showed that the drug was associated with better overall functioning and reduced symptom severity.
      • Atypical drug therapy - clozapine - more effective than typical drugs. used as a last resort as it was linked with deaths of some patients from agranulocytosis - the drug also works on serotonina nd glutamine receptors - helping to improve mood.                Risperidone is similar but more effective as it binds to the receptors more strongly with less side effects, however it is very expensive
      • Healy suggested that successful trials have had their data published multiple times, exagerating the evidence for possible effects.            There are also serious side effects to taking the drugs - typical - dizziness, agitation, sleepiness, tardive dyskinsea.
    • Psychological treatments
      • Cognitive Behavioural Therapy- aim is to help patients identify irrational thoughts and then try and change them.     it helps patients to understand their symptoms.
        • puts patients in charge of their own treatment- more   motivated            however it can interfere with a persons freedoom of thought.
      • Token economies - Reward systems used to manage a persons behaviour in particular those with a maladaptive behaviour due to long periods of time in psychiatric hospitals.
        • There is evidence to show effectiveness in improving quality of life. They help make patients behaviour more socially acceptable. An ethical issue is that tokens are more easily acceptable to those with more mild symptoms.
      • Family Therapy -aims to improve quality of communicatioand interaction between family members
        • Pharaoh et al identified a range of strategies family therapist can use.                  reducing stress and guilt, improving families' beliefs about and behaviour towards SZ
          • families must be engaged and willing to cooperate. Useful for patients who can't express own feelings and therefore can't participate in CBT
    • The Interactionist Approach
      • Diathesis-stress model: Vulnerability + trigger = schizophrenia
        • Meehl's model  Diathesis=  genetics stress= schizophenogenic mother
          • Tienari et al - investigated children adopted from 1900 Finnish mothers with SZ. Adoptive parents were assessed for parenting styles. Children with genetic vulnerability and a high level of criticism and conflict were still at heightened risk of SZ.
            • Too simple - we know multiple genes can increase risk of SZ Houston et al found that sexual trauma could be a vulnerability whilst cannabis use could be a trigger.
        • In the modern version of a diathesis stress model diathesis= many genes, or even early psychological         trauma        stress= anything that risks triggering SZ
      • Treatment - combining drug therapy and CBT is consistent with the approach
        • The UK adopts a more interactionist approach than the US
          • Tarrier showed how medication + CBT or supportive counselling is more beneficial than medication alone at reducing symptoms
            • Treatment-causation fallacy the fact that the combined approach are more effective than one on their owns doesn't mean that the interactionist approach is correct.

Comments

No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all Schizophrenia resources »