Interactionist approach

What is the interactionist approach?

Acknowledges that there are biological, psychological and social factors in the development of schizophrenia

Describe the diathesis stress model in explaining schizophrenia

• Diathesis means vulnerability and stress refers to a negative experience. The diathesis-stress model believes that both a vulnerability to schizophrenia and a stress-trigger are necessary to develop the condition.

• Meehl’s model (1962) In the original model diathesis (vulnerability) was purely genetic, believing in a single ‘schizogene’. This led to a schizotypic personality, which was sensitive to stress. Meehl believed that if an individual did not have this schizogene, then no amount of stress would lead to schizophrenia.

• However, those with the gene who experienced chronic stress through childhood, and in particular the presence of a schizophrenogenic mother, could result in the development of the condition.

Modern understanding of diathesis

• Our modern understanding of diathesis has changed as we now know that many genes appear to increase genetic vulnerability slightly; there is no single ‘schizogene’ (Ripke 2014).

• Diathesis can also include factors beyond the genetic, such as psychological trauma. Early trauma can alter the developing brain development. Early and severe trauma, such as child abuse, can affect many aspects of brain development.

• For example, the hypothalamic-pituitary-adrenal (HPA) system can become over-active making the individual much more vulnerable to later stress.

Modern understanding of stress

• Originally stress was seen as psychological in nature, and in particular related to parenting. The modern definition still acknowledges the stress resulting from parenting may be important, but it also includes anything that risks triggering schizophrenia.

• Much of modern research has looked at cannabis use. Cannabis is a stressor as it increases the risk of schizophrenia by up to seven times according to dose.

• This is probably because cannabis interferes with the dopamine system.

• However, many people do not develop schizophrenia after smoking cannabis so it seems there must also be one or more vulnerability factors.

Describe the interactionist approach to treating schizophrenia

• The interactionist model is 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 to treat patients with a combination of antipsychotic drugs and CBT. However, in the USA it is more common to be treated with just medication than a combination of both medication and therapy than it is in the UK.

• It is unusual to treat schizophrenia using psychological therapies alone. CBT, family therapy and the use of token economies for schizophrenia are usually carried out with patients taking antipsychotics.

Give 1 strength of interactionist approach

• One strength of the interactionist approach to schizophrenia is evidence supporting the role of both vulnerability and stress triggers in development of schizophrenia.

• Tienari investigated the combination of genetic vulnerability and parenting style (the trigger). Children adopted from 19,000 Finnish mothers with schizophrenia were followed up.

• Their adoptive parents were assessed for child-rearing style, and the rates of schizophrenia were compared to a control group of adoptees without any 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 the children with high genetic risk, not the control group.

• This suggests that both genetic vulnerability and family-related stress are important in the development of schizophrenia. This is very strong direct supporting for the interactionist approach to explaining schizophrenia.

GIve 1 limitation of orignal diathesis stress model

• One limitation of the original diathesis-stress model is oversimplicity. It is now clear that the original model that portrayed diathesis as a single schizogene and portrayed stress as schizophrenogenic parenting is overly simplistic. Multiple genes in multiple combinations influence diathesis.

• Stress also comes in many forms, including but not limited to dysfunctional parenting. In fact, diathesis can also be influenced by psychological factors and stress can be biological as well as psychological.

• This is shown in a study by Houston, in which childhood sexual abuse emerged as the major influence on underlying vulnerability and cannabis use as the major trigger.

• This means there are multiple factors, both biological and psychological, affecting both diathesis and stress, supporting the modern understanding of both diathesis and stress.

GIve 1 strength and counter-arguement of interactionist approach

• One further strength of the interactionist approach is in the combination of biological and psychological treatments. A practical application of acknowledging biological and psychological factors in schizophrenia has been the combination of drug treatment and psychological therapies.Studies show that combining treatments enhances their effectiveness.

  • Tarrier (2004) randomly allocated 315 patients to either:

    • 1. Medication + CBT

    • 2. Medication and counselling

    • 3. Control group (medication only)

  • Participants in the two combination groups showed lower symptoms following the trial than the medication-only group, though there was no difference in hospital readmission.

  • This means there is a clear practical advantage to adopting an interactionist approach to schizophrenia in terms of superior treatment outcomes.

• However, Jarvis and Okami point out that saying that a successful treatment for mental disorder justifies a particular explanation is the logical equivalent of saying that because alcohol reduces shyness, shyness is caused by lack of alcohol.

• This logical error is called the treatment- causation fallacy. Therefore we cannot assume that the success of combined therapies means interactionist explanations are correct.