Interactionist Flashcards
Diathesis-stress model (vulnerability+trigger=schizophrenia)
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
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
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
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
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
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.
A03: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.
A03: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.
A03: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.
A03 (counter):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.
