INTERACTIONIST APPROACH

• What is the diathesis stress model for schizophrenia?

  • Suggests that both a vulnerability (genetic) to schizophrenia and an environmental-trigger (stress) are necessary to order to develop the condition.
• Outline Meehl's Model (1962)

  • The diathesis/vulnerability for schizophrenia is entirely genetic
  • Genes are assumed to cause neurochemical abnormalities that result in an increased risk in developing schizophrenia
  • The result of a single ‘schizogene’, if a person does not carry this, no amount of stress would lead to schizophrenia
  • The stress/trigger for schizophrenia is negative psychological experience e.g. dysfunctional parents, stressful life events etc.
• What is the more modern model for diathesis?

  • many genes appear to increase genetic vulnerability, there isn’t one single schizogene (supported by Ripke et al, polygenic)
  • There are many psychological factors that become the diathesis (vulnerability) rather than the stressor
  • READ ET AL proposed neurodevelopmental model in which early trauma alters the developing brain
  • Early and severe trauma can alter the HPA system, hypothalamic-pituitary-adrenal system becoming overactive and making the person more vulnerable to later stress
  • Therefore psychological stress can cause brain damage  
• What can trauma alter? (a modern diathesis)

  • Early and severe trauma can alter the HPA system, hypothalamic-pituitary-adrenal system
  • becoming overactive and making the person more vulnerable to later stress
• What is the modern understanding of stress?

  • Original model included only psychological stress whereas modern understanding includes any environmental factors that could trigger vulnerabilities
  • Some individuals may have a very strong genetic vulnerability to relatively mild stress will trigger, others may have a weaker genetic vulnerability but experience severe stress
• What are some examples of modern stressors that are environmental?

  • E.g. cannabis use which increases the risk of developing SZ up to 7x due to the interference with the dopamine system
  • Living in a highly urbanised environment may also increase risk. 2.4x higher than rural due to adverse living conditions (VASSOS ET AL)
• Research support for requiring a diathesis and stressor (AO3)

  • TIENARI ET AL
  • 145 children who had at least one biological parent with SZ and were adopted into a new family were compared with 158 controls (adoptees without genetic risk)
  • Found that child rearing styles, characterised by high levels of criticism and conflict and low levels of empathy were implicated in the development of schizophrenia, but only for those in the high-genetic risk group
  • SUGGESTS: Both genetic vulnerability and family-related stress are important in the development of schizophrenia, genetically vulnerable children are more sensitive to parenting behaviour
  • direct support for the importance of adopting an interactionist approach to SZ,
• Limitation- Diatheses may not be exclusively genetic

  • The increased risk for schizophrenia can also result from brain damage caused by environmental factors
  • For example, Verdoux et al. (1998) estimated that the risk of developing schizophrenia later in life was 4x greater for those who had experienced prolonged labour and oxygen deprivation than those who hadn’t experienced such complications.
  • Additionally, cannabis may be a stressor as it increases the risk of schizophrenia by up to 7x depending on the dose.
  • This is probably because cannabis interferes with the dopamine system
  • This suggests that the old idea of diathesis-stress may be overly simple
  • However, it still supports that an interactionist approach to schizophrenia is important in that vulnerabilities
• Limitation- stressors in early life (AO3)

  • It is possible that stressors earlier in life can also influence how people respond to later stressful events, and increase their susceptibility to the disorder
  • Maladaptive methods of coping with stress in childhood
  • individual fails to develop effective coping skills, which in turn compromises their resilience and increases vulnerability
  • This may make life generally more stressful for the individual and so trigger schizophrenia
  • Therefore, difficult to determine the causal stress that triggered schizophrenia, which may negatively impact the effectiveness of treatment
• STRENGTH FOR IA IN TREATMENT (AO3)

  • Tarrier et al. (2004)
  • randomly allocated 315 patients to a medication + CBT
  • medication group + supportive counselling group
  • or control group (medication only).
  • found that patients in the two combination groups showed lower symptoms levels than those in the control group
  • although there was no difference in rates of hospital readmission
  • suggests there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes, and therefore highlighting the importance of taking an interactionist approach.