An Interactionist Approach Flashcards
What is the diathesis stress model?
It proposes that schizophrenia is the result of the combination of psychological/environmental and biological/genetic influences. The symptoms are triggered or made worse when significant stressors are combined with genetic vulnerability. This can explain why people who have genetic vulnerability might not develop the disorder.
What is Meehl’s model?
In the original diathesis-stress model, diathesis was entirely the result of a single ‘schizogene’. Meehl 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 (e.g. A schizophrenogenic mother). The schizogene is necessary but not sufficient for the development of schizophrenia.
What is the modern understanding of diathesis?
It is one 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.
What is modern understanding of stress?
A modern definition of stress (in relation to diathesis-stress) includes anything that risks triggering schizophrenia (including psychological stress). For example, cannabis use can increase the risk of schizophrenia up to seven times depending on the dose-probably because it interferes with the dopamine system.
How does the interactionist approach relate to treatment?
It has been suggested that it is possible to believe in biological causes of schizophrenia and still practice CBT to relieve psychological symptoms. But this requires adopting an interactionist approach - 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.
Where adopts a more interactionist approach?
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.
Strength: support for the dual role of vulnerability and stress.
Tienari et al studied children adopted away from schizophrenic mothers. 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 is very strong direct support for the interactionist approach - genetic vulnerability and family-related stress combine in the development of schizophrenia.
Limitation: the original diathesis-stress model is too 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 and diathesis psychological factors. For example, child abuse affects the hypothalamus-pituitary-adrenal system. This shows that the old idea of diathesis as biological and stress as psychological has turned out to be overly simplistic.
Strength: usefulness of the interactionist approach in treatment.
Terrier et al randomly allocated 315 patients to (1) medication and CBT group, (2) medication and supporting counselling group or (3) a control group. Patients in the two combination groups showed lower symptom levels than those in the control group (medication only). But no difference in hospital readmission. Studies like this show that there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes.
Limitation: we don’t know exactly how diathesis and stress work.
There is strong evidence to suggest that some sort of underlying vulnerability coupled with stress can lead to schizophrenia. But we do not understand the mechanisms by which symptoms of schizophrenia appear and how both vulnerability and stress produce them. This does not undermine support for the approach, but it does mean we have an incomplete understanding of the actual mechanism.
Limitation: the treatment-causation fallacy.
It has been argued the fact that combined biological and psychological therapies are more effective than either on their own does not necessarily mean the interactionist approach to schizophrenia is correct. Similarly the fact that drugs help does not mean that schizophrenia is biological in its origin. This error of logic is called the treatment-causation fallacy. It means that the superior outcomes of combined therapies should not be over-interpreted in terms of evidence in support of the interactionist approach.
