The interactionist approach to schizophrenia Flashcards
6 point summary for AO1
The diathesis-stress model
1) Diathesis-stress model (vulnerability+trigger=schizophrenia)
2) Meehl’s model (diathesis is genetic)
3) Modern understanding of diathesis
4) Modern understanding of stress
Treatment according to the interactionist model:
5) Antipsychotic medication and CBT
6) The UK adopts a more interactionist approach compared to the US
Diathesis-stress model (vulnerability+trigger=schizophrenia) AO1 point
Diathesis means vulnerability. Stress in this context refers to negative experiences that trigger the vulnerability. The diathesis-stress model says both a vulnerability and a trigger are needed to develop schizophrenia. Individually may not create schizophrenia - it is the interaction that is key.
Meehl’s model (diathesis is genetic) AO1 point
In the original diathesis-stress model, diathesis was entirely the result of a single ‘schizogene’. Meehl (1962) argued that someone without this gene should never develop schizophrenia, no matter how much stress they were exposed to. But a person who does have the gene is vulnerable to the effects of chronic stress (especially a schizophrenogenic mother). The schizogene is necessary but not sufficient for the development of schizophrenia.
Modern understanding of diathesis AO1 point
It is now believed that diathesis is not due to a single ‘schizogene’. Instead it is thought that many genes increase vulnerability. Also, diathesis doesn’t have to be genetic. It could be early psychological trauma affecting brain development. For example, child abuse affects the hypothalamic-pituitary-adrenal (HPA) system, making a child vulnerable to stress.
Modern understanding of stress AO1 point
A modern definition of stress (in relation to diathesis-stress) includes anything that risks triggering schizophrenia. Can be psychological (e.g. parenting) or biological (e.g. cannabis use). Cannabis use can increase the risk of schizophrenia up to seven times depending on dose - probably because it interferes with the dopamine system.
Antipsychotic medication and CBT AO1 point
Antipsychotic drugs taken in combination with CBT. But this requires adopting an interactionist model - it is not possible to adopt a purely biological approach, tell patients that their condition is purely biological (no psychological significance to their symptoms) and then treat them with CBT (Turkington et al 2006).
The UK adopts a more interactionist approach compared to the US AO1 point
In Britain it is increasingly standard practice to treat patients with a combination of drugs and CBT. In the US there is more of a conflict between psychological and biological models of schizophrenia and this may have led to slower adoption of the interactionist approach.
Support for vulnerability and triggers evaluation
One strength is support for the dual role of vulnerability and stress. Tienari et al (2004) studied children adopted away from mothers diagnosed with schizophrenia. The adoptive parents’ parenting styles were assessed and compared with a control group of adoptees with no genetic risk. A child-rearing style with high levels of criticism and conflict and low levels of empathy was implicated in the development of schizophrenia but only for children with a high genetic risk. This shows that a combination of genetic vulnerability and family leads to increased risk of schizophrenia.
Diathesis and stress are complex evaluation
One limitation of the original diathesis-stress model is it is over simplistic. Multiple genes increase vulnerability, each with a small effect on its own - there is no schizogene. Stress comes in many forms, including dysfunctional parenting. Researchers now believe stress can also include biological factors. For example, Houston et al (2008) found childhood sexual trauma was a diathesis and cannabis use a trigger. This means that there are multiple factors, biological and psychological, affecting both diathesis and stress.
Real-world application evaluation
Another strength is real world application of interaction. Tarrier et al (2004) randomly allocated 315 participants to (1) medication + CBT group, or (2) medication + supportive counselling group, or (3) control group (medication only). Participants in the two combination groups showed lower symptom levels than those in the control group - but no difference in hospital readmission. This means that there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes.
Counterpoint for real world application evaluation
Jarvis and Okami (2019) suggest that this argument is the same as claiming that because alcohol reduces shyness, shyness is caused by a lack of alcohol. This logical error is called the treatment-causation fallacy. Therefore we cannot automatically assume that the success of combined therapies means interactionist explanations are correct.
Interactionist approach
a way to explain the development of behaviour in terms of a range of factors, including both biological and psychological ones. Most importantly such factors don’t simply add together but combine in a way that can’t be predicted by each one separately i.e. they interact.
Diathesis-stress model
an interactionist approach to explain behaviour. For example schizophrenia is explained as the result of both an underlying vulnerability (diathesis) and a trigger (stressor), both of which are necessary for the onset of schizophrenia. In early versions of the diathesis-stress model, vulnerability was genetic and triggers were psychological. Nowadays both genes and trauma are seen as diathesis, and stress can be psychological or biological in nature.
