L6 - The Interactionist Approach In Explaining & Treating SZ - The Diathesis-Stress Model

Question 1

What is the interactionist approach?

Answer 1

• also referred to as the bio social approach
• it acknowledges that there are biological, psychological and societal factors in the development of SZ.
• Biological factors include genetic vulnerability and neurochemical (e.g. dopamine) and neurological (brain) abnormality.
• Psychological factors include stress resulting from life events (such as losing a loved one, moving country etc) and daily hassles (such as concern about weight, worried about appearance) and including poor quality interactions in the family

Question 2

The diathesis-stress model - explaining the onset of SZ

Answer 2

• Diathesis means vulnerability – we have seen that SZ has a genetic component
• in this context stress simply means a negative psychological experience.
• model states that both a vulnerability to SZ and a stress-trigger are necessary in order to develop the condition.
• One or more underlying factors make a person particularly vulnerable to developing SZ but the onset of the condition is triggered by stress.

Question 3

Original diathesis-stress model

Answer 3

• Meehl’s model – 1962 diathesis was entirely genetic and there was one specific gene ‘schizogene’.
• This led to the idea 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 SZ.
• However, in carriers of the gene, chronic stress through childhood and adolescence especially the presence of the schizophrenogenic mother could result in the development of the disorder.

Question 4

Modern understanding of diathesis-stress model

Answer 4

• it’s clear that many genes increase genetic vulnerability and there is no single gene.
• Modern views of diathesis include genes but also psychological trauma (Ingram and Luxton, 2005) so trauma becomes the diathesis rather than the stressor.
• Read et al. (2001) proposed a neurodevelopmental model in which early trauma affects lbrain development.
• In fact, early and severe enough trauma such as child abuse can seriously affect brain development e.g. HPA (hypothalamic pituitary adrenal)systems can become overactive making the person more vulnerable to stress
• The modern understanding of stress is opposed to the original understanding of it (which was that stress was psychological in nature and due to parenting), is that it is anything that risks triggering schizophrenia e.g. cannabis use which makes it 7 times more likely for a person to develop schizophrenic symptoms.
• This is because cannabis interferes with the dopamine system – although most people do not develop SZ through cannabis use as most people do not take cannabis but will develop SZ – this suggests that there are clearly other stressors which contribute to the development of SZ.

Question 5

Treatment of SZ according to the interactionist approach

Answer 5

• The interactionist model of SZ acknowledges both biological and psychological factors in SZ and is therefore compatible with both biological and psychological treatments – in particular the model is associated with combining antipsychotic medication and psychological therapies such as CBT.
• In Britain it is increasingly standard practice t treat patients with a combination of drugs and CBT.
• It’s unusual to treat SZ using psychological therapies alone this is because SZ is a complex psychotic disorder, drug therapy will be first given to control the symptoms of SZ, the drug therapy will be used
  in a hospital setting perhaps with token economy to manage the behaviour of patients
  with SZ.
• Then CBT and family therapy will precede this.

Question 6

Evaluation

Answer 6

strengths
- Evidence for the role of vulnerability and triggers
- Support for the effectiveness of combination of treatments
weaknesses
- too simplistic
- don’t know how it exactly works
- treatment-causation fallacy

Question 7

Evidence for the role of vulnerability and triggers

Answer 7

• there is research support for the dual role for genetic vulnerability to SZ and stress triggers.
  E.g. Tienari 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 SZ.

Question 8

Support for the effectiveness of combination of treatments

Answer 8

• Another strength is the usefulness of the interactionist approach in treatment of SZ – Tarrier et al.
  (2004) randomly allocated 315 patients to (1) medication and CBT group or (2) a,medication and supportive counselling group, or (3) a control group.
• Patients in the two combination groups (groups 1 and 2) 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.

Question 9

Too simplistic

Answer 9

• 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.
  E.g. Houston et al. (2008) found childhood sexual trauma was a diathesis and cannabis use a trigger.
• This shows that the old idea of diathesis as biological and stress as psychological has turned out to be overly simple

Question 10

Don’t know how the diathesis-stress model works exactly

Answer 10

• There is strong evidence to suggest that some sort of underlying vulnerability coupled with stress can lead to schizophrenia.
• But we don’t 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 medication

Question 11

Treatment-causation fallacy

Answer 11

• Turkington et al. (2006) argue 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 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.
• This means that both the cause of SZ and how it is treated should be taken with caution and assumptions should not be made.