Interactionist Approach to Explaining and Treating SZ

• Diathesis-stress model


  both a vulnerability to SZ and a stress trigger are necessary in order to develop the disorder.
• Meehl's Model (original diathesis-stress)

  original model says diathesis is entirely genetic, a single 'schizogene'

  results in a schizotypic personality including increased vulnerability to stress

  Meehl says no schizogene = no SZ

  carriers of gene + chronic stress + presence of schizophrenogenic mother
• Modern Diathesis


  no schizogene

  diathesis includes a range of factors e.g. trauma

  Read says early trauma alters the developing brain. early and severe enough trauma such as child abuse, can seriously affect many aspects of brain.

  For example, HPA axis can become overactive, making a person more vulnerable to later stress.
• Modern Stress


  originally mostly psychological and due to parenting e.g. schizophrenogenic mother. now it includes anything that could trigger SZ.

  recent research look at cannabis use.

  Cannabis is a stressor because it increases the risk of SZ by up to 7times according to dose. this is because cannabis interferes with the dopamine system. However, most people don't develop SZ after smoking cannabis presumably as they lack the requisite vulnerability factors.
• Benefits of taking antipsychotics alongside a psychological therapy

  acknowledges both biological and psychological factors in SZ.

  antipsychotics reduce the symptoms to allow treatment to work better -> combination with CBT

  Turkington - it's possible to believe in biological causes of SZ and still practice CBT to relieve psychological symptoms.

  requires adopting an interactionist model -> not possible to adopt a purely biological approach and tell people diagnosed with SZ that their condition is purely biological and there's no psychological significance to symptoms, and then simultaneously treat them with CBT
• Strength - evidence for the vulnerability and triggers

  Tiernari et al investigated the

  combination of genetic vulnerability and stress in development of SZ.

  children adopted from 19,000 Finnish mothers with SZ between 1960-79 were followed up. their adoptive parents were assessed for child-rearing style and rates of SZ were compared to a control group.

  Results: high levels of criticism and conflict and low level of empathy was implicated in development of SZ but only for children with high genetic risk but not in the control group.

  Very strong direct support for importance of adopting an interactionist approach to SZ, including hanging onto the idea that poor parenting is a possible source of stress.
• Weakness - original diathesis stress is oversimplistic

  classic model of a single schizogene and schizophrenic parenting style as a major source is known to be over-simplistic.

  multiple genes increase the vulnerability to SZ, each having a small effect on its own, there's no single schizogene.

  Also, stress can come in many forms, including dysfunctional parenting.

  vulnerability and stress doesn't have one single source
• Strength - support for effectiveness of combinations of treatments

  support from studies comparing effectiveness of combinations of biological and psychological treatments for SZ vs biological alone.

  Turkington et al points out it's not really possible to use combination treatments without adopting the interactionist approach

  Tarrier et al - 315 patients were randomly allocated to a medication and CBT group, medication + supportive counselling or a control group.

  patients in 2 combination groups showed lower symptom level than those in the control group.

  studies show there's a clear practical advantage to adopting an interactionist approach in the form of superior treatment alone, therefore highlighting the importance of taking an interactionist approach