'Discuss the interactionist approach to schizophrenia' (16 marks)

The interactionist approach acknowledges that there are...

Biological, psychological and societal factors in the development of schizophrenia

Biological factors include...

Genetic vulnerability and neurochemical and neurological abnormality

Psychological factors include...

Stress, for example, resulting from life events and daily hassles, including poor quality interactions in the family

The diathesis-stress model is an...

Interactionist approach to explaining behaviour

The diathesis-stress model says that both a...

Vulnerability to schizophrenia and a stress-trigger are necessary in order to develop the condition

One or more underlying factors makes a person particularly...

Vulnerable to developing schizophrenia but the onset of the condition is triggered by stress

Who was the original diathesis-stress model put forward by?

Meehl, 1962

In the original diathesis-stress model, diathesis (vulnerability) was entirely...

Genetic, the result of a single schizogene

In the original diathesis-stress model diathesis was genetic, the result of a single schizogene and what did this lead to?

The development of a biologically based schizotypic personality, one characteristic of which is sensitivity to stress

According to Meehl, if a person does not have the schizogene then...

No amount of stress would lead to schizophrenia

However, in carriers of the (schizo) gene, chronic stress through...

Childhood and adolescence could result in the development of the condition

One way in which our understanding of diathesis has changed is that it is now clear that...

Many genes each appear to increase genetic vulnerability slightly; there is no 'schizogene' evident in Rpike et al's study

Modern views of diathesis also include a range of factors beyond the genetics, including...

Psychological trauma-so trauma becomes the diathesis rather than the stressor

Early and severe enough trauma, such a child abuse, can...

Seriously affect many aspects of brain development

What is an example of child abuse affecting many aspects of brain development?

The hypothalamic-pituarity-adrenal system can become overactive, making the person much more vulnerable to later stress

In terms of stress, the original diathesis-stress model showed stress was seen as...

Psychological in nature, in particular related to parenting

Although psychological stress still is considered important, a modern definition of stress...

Includes anything that risks triggering schizophrenia

Much of the recent research into factors triggering an episode of schizophrenia has concerned...

Cannabis use

In terms of the diathesis-stress model, cannabis is a...

Stressor because it increases the risk of schizophrenia by up to seven times according to the dose

Why does cannabis increase the risk of schizophrenia?

Probably because it interferes with the dopamine system

However, most people do not develop schizophrenia after smoking cannabis os it seems...

There must also be one or more vulnerability factors

The interactionist model of schizophrenia acknowledges both biological and psychological factors in schizophrenia and is therefore compatible with...

Both biological and psychological treatments

In particular, the model is associated with combing...

antipsychotic medication and psychological therapies, most commonly CBT.

What does Douglas Turkington et al (2006) point out...

It is perfectly possible to believe in biological causes of schizophrenia and still practice CBT. However this requires adopting an interactionist model.

In Britain, it is increasingly standard practice to treat patients with a...

Combination of antipsychotic drugs and CBT

In the USA there is more of a history of conflict between...

Psychological and biological models of schizophrenia and this may have led to slower adoption of an interactionist approach

It is unusual to treat schizophrenia using psychological...

Therapies alone. CBT, family therapy and the use of token economies with sufferers of schizophrenia are usually carried out with patients taking antipsychotics.

What is one strength of the interactionist approach?

One strength is support for the dual role of vulnerability and stress. Tiernari et al (2004) 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.

What is another strength for the interactionist approach?

Another strength is the usefulness of the interactionist approach in treatment. Tarrier et al (2004) randomly allocated 315 patients to three different groups. These groups were medication and CBT group, medication and supportive counselling group and a control group. Patients in the two combination groups showed lower symptom levels than those in the control group, which was 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.

What is one limitation of the interactionist approach?

One limitation is that 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 include biological factors. For example, Houston et al (2008) found childhood sexual trauma was a diathesis and cannabis use as a trigger. This shows that the old idea of diathesis as biological and stress as psychological has turned out to be overly simple.

What is another limitation of the interactionist approach?

Another limitation is that we don't know exactly how diathesis and stress work. This 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 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.