the interactionist approach to schizophrenia

Question 1

the interactionist approach

Answer 1

• acknowledges there are biological, psychological and social factors in development of schizophrenia
• biological factors such as genetic vulnerability
• psychological factors such as stress
• social factors such as poor family interactions

Question 2

the diathesis-stress model

Answer 2

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

Meehl’s model -
- in original diathesis-stress model, diathesis was entirely genetic as the result of a single ‘schizogene’
- led to idea of biologically based schizotypic personality, one characteristic of this is sensitivity to stress
- Meehl said that if a person doesn’t have the schizogene then no amount of stress would lead to schizophrenia
- however, in carriers of the gene, chronic stress through childhood and adolescence, and the presence of a schizophrenogenic mother, could result in development of the disorder

modern understanding of diathesis -
- now clear that many genes increase genetic vulnerability, no single ‘schizogene’
- modern views also include range of factors beyond genetic, including psychological trauma (so trauma becomes the diathesis rather than the stressor)
- John Read proposed neurodevelopmental model where early trauma alters the developing brain
- early and severe enough trauma can affect many aspects of brain development

modern understanding of stress -
- in the original model, stress seen as psychological in nature, in particular related to parenting
- modern definition of stress includes anything that risks triggering schizophrenia, recent research has concerned cannabis use
- in terms of diathesis-stress model, cannabis is a stressor because it increases risk of schizophrenia by up to 7X according to dose
- maybe because cannabis interferes with dopamine system
- however, most people do not develop schizophrenia after smoking cannabis, presumably because they lack the vulnerability factors

Question 3

treatment according to the interactionist model

Answer 3

• interactionist model acknowledges both biological and psychological factors, therefore compatible with both treatments
• in particular, associated with combining antipsychotic medication and psychological therapies such as CBT
• Douglas Turkington points out it is perfectly possible to believe in biological causes of schizophrenia and still practise CBT to relieve psychological symptoms
• however this requires adopting an interactionist model, not possible to adopt purely biological approach and then simultaneously treat with CBT
• in Britain, increasingly standard practice to treat people with antipsychotic drugs and CBT
• in US, more history of conflict between psychological and biological models of schizophrenia, slower adoption of interactionist approach
• medication without accompanying psychological treatment is more common in US

Question 4

evaluation strength - support for vulnerability and triggers

Answer 4

• Tienari investigated impact of genetic vulnerability and a psychological trigger (dysfunctional parenting)
• study followed 19,000 Finnish children whose biological mothers had been diagnosed with schizophrenia
• in adulthood, this group were compared to control group of adoptees without family history of schizophrenia
• adoptive parents assessed for child-rearing style
• high levels of criticism, hostility and low levels of empathy were strongly associated with development of schizophrenia, only in high genetic risk group
• shows that combination of genetic vulnerability and family stress can lead to greatly increased risk of schizophrenia

Question 5

evaluation limitation - diathesis and stress are complex

Answer 5

• now clear that original model that portrayed diathesis as single schizogene and portrayed stress as schizophrenogenic parenting was very simplistic
• multiple genes in multiple combinations influence diathesis
• stress comes in many forms, not limited to dysfunctional parenting
• study by Houston showed that diathesis can also be influenced by psychological factors, and stress can be biological too
• there are multiple factors, both biological and psychological, affecting both diathesis and stress
• supported the modern understanding of the model

Question 6

evaluation strength - real-world application

Answer 6

• practical application of acknowledging biological and psychological factors in schizophrenia has been combination of drug treatment and psychological therapy
• studies show that combining treatments enhances effectiveness
• Tarrier randomly allocated 315 participants to 1) medication + CBT, 2) medication + counselling, or 3) control group (medication only)
• participants in combination groups showed lower symptoms following the trial than the control group, though there was no difference in hospital readmission
• there is clear practical advantage to adopting interactions approach in terms of superior treatment outcomes

Question 7

evaluation limitation - counterpoint to real-world application

Answer 7

• Jarvis and Okami pointed out that saying that a successful treatment for mental disorders justifies a particular explanation is the equivalent of saying that because alcohol reduces shyness, shyness is caused by lack of alcohol
• this error is caused the treatment-causation fallacy
• we cannot automatically assume that the success of combined therapies means that interactions explanations are correct