A01

• What is the interactionist approach to schizophrenia (diathesis-stress model)?

  Explains schizophrenia as the result of an interaction between biological (the diathesis) and environmental (stress) influences
• What does Meehl's (1962) original diathesis-stress model state?

  • That diathesis (vulnerability) is entirely genetic and the result of a single schizogene which leads to a biologically based schizotypic personality (extremely sensitive to stress)
  • No amount of stress will lead to schizophrenia if the gene is not present
  • Stress is seen as psychological in nature, normally related to dysfunctional parenting (schizophrenogenic mother)
• What does the modern understanding of diathesis entail?

  • Many genes each can increase genetic vulnerability, not just one gene (schizophrenia is polygenic)
  • Also diathesis can be more than just genetics - e.g. psychological trauma (child abuse)
• What does the term diathesis mean?

  Vulnerability
• What combination of treatment would an interactionist model use?

  Antipsychotics and CBT
• What is one study which shows support for an interactionist approach for schizophrenia?

  Tienari (2004)
• What were the results of Tienari's study?

  Found that child-rearing style only affected the development of schizophrenia in children who had a high genetic risk
• What is one study which shows the effectiveness of a combination of treatment for schizophrenia?

  Tarrier et al. (2004)
• What were the findings of Tarrier et al.'s study?

  Patients who were given a combination of either medication and CBT or medication and supportive counselling showed lower symptom levels than those who had medication only
• Why is the original diathesis-stress model oversimplified?

  • Claims that schizophrenia is caused by one single 'schizogene', whereas research has shown there are multiple genes involved
  • Also other factors other than genes that can lead to a diathesis for schizophrenia
• What is the diathesis-stress model for schizophrenia?

  States that people can have a predisposition to develop schizophrenia (diathesis), but this disorder will only develop if it is triggered by a stressful environment (stress)
• What does the modern understanding of stress entail?

  Anything that risks triggering schizophrenia (e.g. cannabis), not just parenting
• What is the study which found cannabis has triggered a lot of schizophrenic episodes?

  Houston et al. (2008)
• What were the findings of Houston et al.’s (2008) study?

  • Established that cannabis had triggered a lot of schizophrenic episodes in patients
  • Cannabis = a stressor as it increases risk of schizophrenia by up to seven times
  • Cannabis interferes with the dopamine system
  • Individuals will only be at risk of developing schizophrenia after smoking cannabis if they have the diathesis (the vulnerability)
• What study suggests that diathesis is more than just genetics?

  Read (2001)
• What were the findings of Read’s (2001) study?

  • Proposed a Neurodevelopmental model where psychological trauma is seen as the diathesis
  • It has been found that early trauma alters the developing brain
  • For example, hypothalamic - pituitary - adrenal (HPA) system can become overactive making a person more vulnerable to later stress