8. the interactionist approach

Key terms

Interactionist approach — a way to explain development including biological and psychological factors. These factors interact

Diathesis-stress model — an interactionist approach to explaining behaviour. E.g schizophrenia is explained as the result of an underlying vulnerability (diathesis) and a trigger (stressor)

The interactionist approach

  • acknowledges there are biological, psychological and social factors in the development of schizophrenia

  • Biological factors = genetic vulnerability, neurochemical and neurological abnormality

  • Psychological factors = stress

  • Social factors = poor quality interactions in the family

Diathesis stress model

  • says that both a vulnerability to schizophrenia and a stress-trigger are necessary to develop the disorder

Meehls model

  • if a person doesn’t have a schizogene then no amount of stress would lead to schizophrenia

  • However in carriers of the gene chronic stress through childhood and adolescence, in particular the presence of a schizophrenogenic mother, could result in the development of the disorder

Modern understanding of diathesis

  • now clean that many genes increase genetic vulnerability, there is no single ‘schizogene’

  • There are also factors beyond genetic, such as psychological trauma. So this becomes the diathesis rather than the stressor

  • John Read proposed a neurodevelopmental model in which early trauma alters the developing brain. E.g the hypothalamic-pituitary-adrenal system may become overactive so they are more vulnerable to later stress, makes people 2-3% more likely to develop schizophrenia

Treatment

  • compatible with both biological and psychological treatments, such as combining antipsychotic medication and psychological therapies such as CBT

  • Turkington suggests that its not possible to adopt a purely biological approach and then to simultaneously treat them with psychological therapies such as CBT

Evaluation

Support for vulnerability and triggers

  • Tienari carried out a large scale study, investigating the impact of both genetic vulnerability and a psychological trigger (dysfunctional parenting)

  • Followed 19,000 Finnish adopted children whole biological mothers had been diagnosed with schizophrenia, these were compared to a control groups without a family history of schizophrenia

  • Adoptive parents had been assessed for child-rearing style, found that high criticism, hostility and low levels of empathy were associated with the development of schizophrenia in the high genetic risk group

Diathesis and stress are complex

  • oversimplified, the original model portrayed diathesis as a single schizogene and stress as schizophrenogenic parenting

  • However there are multiple factors, both biological and psychological, that affect both diathesis and stress

  • E.g Houston found that childhood sexual abuse was the diathesis and cannabis use was the trigger/ stress

Real world application

  • Able to combine biological and psychological treatments

  • Studies show that combining treatments enhances their effectiveness

  • Tarrier randomly allocated 315 participants to 3 groups: medication + CBT, medication + counselling, control/ medication only

  • Participants in group 1+2 showed lower symptoms following the trial

  • This suggests a clear practical advantage to the interactionist approach

— counterpoint — Jarvis suggests that successful treatment cannot be used to justify a particular explanation. Compared it to saying that because alcohol reduces shyness, shyness if caused by lack of alcohol

Urbanisation

  • schizophrenia is more commonly diagnosed in urban areas

  • This can be used to justify the interactionist approach as urban living is more stressful so can act as a trigger

  • However it may just be that schizophrenia is more likely to be diagnosed in cities, or that people with a diathesis for schizophrenia (e.g teenagers that were abused as children) tend to migrate to cities