Interactionist approach:

• The diathesis-stress model


  Is one way to present an interactionist approach

  In this context stress simply means a negative experience.

  • States both a vulnerability to schizo and an stress-trigger are necessary in order to develop the disorder
  • One or more underlying factors make a person particularly vulnerable to developing schizophrenia but the onset of the condition is triggered by stress
• The diathesis-stress model:


  Meehl's model:

  In the original diathesis-stress model (Meehl) diathesis was entirely genetic, the result of a single 'schizogene

  • Led to the idea of a biologically based schizotypic personality, one characteristic of which is sensitivity to stress
  • According to Meehl if a person does not have the schizogene then no amount of stress would lead to schizophrenia
  • However, in carriers of the gene, chronic stress through childhood, in particular the presence of a schizophrenogenic mother, could result in the development of the disorder
• Modern understanding of diathesis


  Understanding diathesis has changed as now its clear that many genes appear to increase genetic vulnerability only slightly, there is no single 'schizogene' (Ripke et al)

  • Modern views of diathesis include a range of factors beyond genetic including psychological trauma (Ingram and Luxton) trauma is the diathesis rather than the stressor
  • Read et al proposed neurodevelopmental model in which early trauma ie child abuse, alters the brain by affecting aspects of brain development
  • IE HPA system can become overactive making a them more vulnerable to later stress
• Modern understanding of stress

  OG diathesis-stress model sees stress as psychological in nature particular related to parenting

  • Stress includes that from parenting may still be important, a modern definition of stress includes anything that risks triggering schizo (Houston et al)
  • Recent research into factors triggering an episode has concerned cannabis
  • Terms of diathesis-stress model cannabis = stressor as it increases the risk by up to 7X according to dose
  • May be as it interferes with the DA system
  • Most ppl dont develop schizo after smoking presumably to the lack vulnerability factors