Interactionist Approach to Schizophrenia

• Interactionist Approach:

  Referred to as the 'biosocial' approach which acknowledges that there are biological, psychological, and societal factors in the development of SCZ. Biological- genetic vulnerability, neurochemical abnormality. Psychological- stress, poor interactions within the family.
• Explaining the Interactionist Approach: Diathesis-Stress Model

  Diathesis means vulnerability, and stress refers to a negative psychological experience. It says that a vulnerability to SCZ and a stress-trigger are necessary to develop the condition. One or more underlying factors make an individual more vulnerable, but the onset of the condition is triggered by stress.
• Diathesis-Stress Model: Meehl's Model

  This is the original diathesis-stress model, where the diathesis was entirely genetic, the result of a single 'schizogene'. Leading to the development of the schizotypic personality, one characteristic is sensitivity to stress. Meehl claims that someone without the schizogene can experience extreme amounts of stress, but don't develop SCZ. However, those with the gene who have experienced chronic stress through childhood and adolescence the develop SCZ (especially the presence of a schizophrenogenic mother).
• Diathesis-Stress Model: Modern Understanding of Diathesis

  It is now clear that many genes appear to increase genetic vulnerability, meaning there is no individual 'schizogene' (Ripke et al). Modern perspectives also include a range of factors beyond genetic, including psychological trauma (Ingram and Luxton)- so trauma becomes the diathesis rather than the stressor.
• Diathesis-Stress Model: Modern Understanding of Diathesis

  Read proposed a neurodevelopmental model where early trauma alters the developing brain. Early and severe trauma, such as child abuse, can seriously impact various elements of brain development. E.g. the hypothalamic pituitary adrenal (HPA) system can become over-active, making the individual more vulnerable to later stress.
• Diathesis-Stress Model: Modern Understanding of Stress

  Originally, stress was seen as psychological, particularly linked to parenting. Although this is still considered important, a modern definition of stress includes anything which risks triggering SCZ; Houston et al. Research has looked into cannabis use, increasing the risk of SCZ up to 7 times according to dosage. Possibly due to cannabis interfering with the dopamine system. However, most people don't develop SCZ after smoking it, so there must be some vulnerability factors.
• Interactionist Model: Treatment

  The diathesis-stress explanation is compatible with the biological and psychological treatments. Particularly, this model is associated with combining antipsychotic medication and psychological therapies like CBT. Turkington et al claims that it is possible to believe in biological causes and still practice CBT to relieve the psychological symptoms, but it requires adopting the interactionist model.
• Interactionist Model: Treatment

  In Britain, it is increasingly standard practice to treat people with a combination of antipsychotic drugs and CBT. In the US, there is a history of conflict between both models of SCZ leading to a slower adoption of the interactionist approach, meaning it is more common to have the medication without the psychological treatment. It is unusual to treat SCZ with psychological therapies alone, instead CBT and token economies are usually carried out on people taking antipsychotics, this may help their engagement with the therapies.
• AO3: Evidence for the Role of Vulnerability & Triggers

  There is evidence to support the dual role of vulnerability and stress in SCZ development. Tienari et al investigated genetic vulnerability and parenting style (stressor). Children adopted from SCZ mothers were followed up in their adoptive families which were assessed for child-rearing style, and compared to a control group with no family history. Styles with high levels of criticism and conflict and low empathy implicated the development of SCZ, only in those with genetic risk. Supporting the interactionist approach.
• AO3: The Original Diathesis-Stress Model is Over-Simple

  It is now known that multiple genes increase the vulnerability to SCZ, each having a small effect on their own- there is no single 'schizogene' it is polygenic. Also, stress comes in many forms. Vulnerability and stress don't have a single source. It is believed that vulnerability can be the result of early trauma and genetic make-up, and stress can be biological. Houston found that childhood sexual trauma emerged as a vulnerability, and cannabis use was a trigger. Showing Meehl's model is reductionist.
• AO3: Support for the Effectiveness of Combined Treatment

  Studies show an advantage to using combination treatments; Tarrier et al studied 315 people with SCZ who were randomly allocated to a medication & CBT group, medication & counselling, or a control group (medication only). People in the 2 combined groups showed lower symptom levels than those in the control group. However there was no difference in hospital re-admission rates. These studies show there is a clear practical advantage.
• AO3: Unclear How Diathesis and Stress Work

  There is strong evidence to suggest that underlying vulnerabilities coupled with stress can lead to SCZ. We have well-informed suggestions for how vulnerabilities and stress may lead to symptoms- however, we don't fully understand the mechanisms which produce the symptoms of SCZ, and how the vulnerability and stressor produce them. Correlation / Causation - lack of clarity over concept.
• AO3: The Treatment-Causation Fallacy

  Turkington et al argue that there is a good logical fit between the interactionist approach and the use of combination treatments. However, the fact that combined biological and psychological treatments are more effective treatments than individually doesn't mean that interactionism is correct at explaining SCZ. Similarly, the fact that drugs help doesn't mean that SCZ is biological in origin. This error in logic is the treatment-causation fallacy where we are unaware if the treatment is actually curing the root cause, as it is unknown for SCZ.
• IDA- Holism

  This refers to studying the disorder as an indivisible system rather than in its constituent parts, this then means it accounts for individual differences better as the onset isn't reduced to one universal law. It considers a variety of circumstances, both in our nature and nurture, and looking at their combined impacts rather than attempting to untangle them.