Interactionism

Interactionist Approach:

• It is becoming increasingly clear that no single explanation of schizophrenia is good enough

• Interactionist models provide a way of combining alternative explanations to give a more complete picture of schizophrenia

• Interactionists also help explore combinations of treatment that can be more effective than any single approach

• The Diathesis Stress Model is the most useful way to understand this approach

  • It proposes that psychological stressors act as a trigger for the expression of underlying biological vulnerability

The Diathesis-Stress Model combines Biological and Psychological Factors:

1. The biological approach to schizophrenia has been criticised for being a reductionist theory.

2. It attempts to explain schizophrenia by reducing it down into the simplest, smallest components possible, such as genetics, neurotransmitters and parts of the brain.

3. An interactionist approach does the opposite — it assumes that processes interact with each other to cause behaviour.

4. For instance, to explain schizophrenia, an interactionist approach looks at a combination of biological and psychological factors:

   • The diathesis-stress model proposes that people who are biologically vulnerable to developing a mental disorder may be more likely to develop it if they are subjected to certain social or environmental stressors.

   • Lots of research has been conducted in this area. The fact that concordance rates in twin studies (see page 143) aren't 100% indicates that there does seem to be some genetic link, but that other factors must play a role as well.

• Biological vulnerability:

  • Genes

  • Biochemical

  +

• Environmental stressor

  • E.g. Job worries

  • Family Problems

  • Money worries

  +

• Schizophrenia

The Diathesis Stress Model:

• Diathesis means vulnerability, in this context, Stress simply means a negative psychological experience

• 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 make a person particularly vulnerable to developing schizophrenia but the onset of the condition is triggered by stress

Meehl’s model:

• Meehl’s model- in the original model diathesis (vulnerability) was entirely genetic, the result of a single schizogene

• This led 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 gene, chronic stress through childhood could result in the development of schizophrenia

Modern understanding (Diathesis):

• One way the understanding has changed is that it is now clear that many genes each appear to increase the genetic vulnerability slightly and there is no single schizogene

• Modern views also include a range of factors beyond genetics, including psychological trauma. So trauma becomes the diathesis rather than the stressor

Read et al (2001) neurodevelopmental model:

• Early trauma alters the developing brain

• Early and severe enough trauma such as child abuse, can seriously affect many aspects of brain development

• For example, the hypothalamic-pituitary-adrenal (HPA) system can become overactive, making the person much more vulnerable to later stress

Modern understanding (Stress):

• In the original model, stress was seen as psychological in nature, in particular related to parenting

• Although psychological stress, including parenting, may still be considered important, a modern definition of stress includes anything that risks triggering schizophrenia

• Much 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 7 times

  • This is properly because cannabis interferes with the dopamine system