The interactionist approach inc treatments

• The interactionist approach acknowledges a wide variety of factors

  • biological
  • psychological
  • societal

  The diathesis-stress model is an interactionist approach explaining schizophrenia as a result of both an underlying (biological) vulnerability (diathesis) and an environmental trigger (stress)
• Explaining schizophrenia

  • the genetic vulnerability is the diathesis
  • it interacts with one or more psychological/environmental factor, this is the stressor
  • claiming that a combination of BOTH factors trigger the development of schizophrenia
  • those who are most genetically at risk of schizophrenia are most vulnerable to environmental triggers
• the genetic vulnerability is the NATURE side of the debate

  the stressor is the NURTURE side of the debate
• More recent interpretations of this model:

  • suggests a number of genes increase vulnerability
  • 'diathesis' has been extended to include psychological trauma (not just genetic inheritance)
  • including environmental trauma
  • early severe trauma e.g. child abuse can affect brain development -> the HPA system can become overactive and more vulnerable to later stress
  • the definitions of stress (stressor) has also been extended beyond family functioning
  • cannabis use is an important factor, its thought to increase the risk of schizophrenia by up to 7 times - interferences with the dopamine system
• Strengths

  • Tienari
  • followed children adopted from 19,000 Finnish schizophrenic mothers
  • the adoptive parents were assessed for child-rearing style
  • a child-rearing style with high levels of criticism and conflict, and low levels of empathy was implicated in the development of SZ BUT only for genetically vulnerable children (not the control group)
  • clearly shows that genetically vulnerable children were more sensitive to parenting behaviour
  • supports the model, suggesting the development of SZ is triggered by a combination of factors
  • Face validity - suggesting both nature and nurture play a role in such a complex disorder
  • not either exclusively biological or environmental causes
  • also explains why twin studies don't show 100% concordance - genetics are only a vulnerability and environmental triggers are required
  • greater stress for one twin may mean they are more likely to develop schizophrenia than the other
• Another strength...

  • it can explain the wide range of differing characteristics and symptoms individuals experience
  • because there may be numerous differing combinations of vulnerability and stress, leading to specific and unique symptoms and experiences
  • for example - a genetic vulnerability (diathesis) with minimal family stressor (stressor) may have completely different symptoms to an early trauma vulnerability (diathesis) with a substance abuse trigger (stressor)
  • the interactionist explanation can explain these differences in symptoms, increasing its validity
• Limitations

  • Low predicitve validity
  • due to the wide variety of vulnerabilities and stressors, from biological, environmental, psychological and social factors its not known how exactly these risks contribute to the diathesis-stress interaction (particularly for each person)
  • low predictive validity - can't be predicted or anticipated how these factors will affect the individual OR how likely they are to develop SZ