Interactionist Approach to Schizophrenia

• The Interactionist Approach to Schizophrenia

  - acknowledges the biological, psychological and social factors of schizophrenia

  
  

  - e.g. genetic vulnerability, stress, interactions in the family
• Diathesis-Stress Model of Schizophrenia

  - diathesis = vulnerability

  
  

  - stress = negative experience

  
  

  - both a vulnerability to schizophrenia and a stress-trigger are needed to develop the disorder

  
  

  - one or more underlying factors may make a person vulnerable to schizophrenia but the onset of the condition is triggered by stress
• Meehl's Model of Schizophrenia (1962)


  - diathesis was entirely genetic caused by a single 'schizogene'

  
  

  - this led to a schizotypic personality characterised by sensitivity to stress

  
  

  - this is what causes schizophrenia; if a person doesn't have this gene no amount of stress can cause schizophrenia

  
  

  - if carriers of the gene experience chronic stress throughout childhood and adolescence (particularly a schizophrenogenic mother) can cause the disorder
• Modern Understanding of Diathesis

  - it has now been shown that schizophrenia is polygenic and is caused by no one gene (Ripke et al, 2014)

  
  

  - each gene only appears to increase genetic vulnerability slightly

  
  

  - psychological trauma is also viewed as a diathesis as well as a stressor

  
  

  - (Read, 2001) proposed a neurodevelopmental model in which early trauma alters the developing brain

  
  

  - e.g. trauma like child abuse can make the hypothalamic-pituitary-adrenal (HPA) overactive making a person more vulnerable to stress
• Modern Understanding of Stress

  - the modern definition is no longer just psychological in nature but now includes anything that risks triggering stress (Houston et al, 2008)

  
  

  - cannabis use has been implicated in causing schizophrenic episodes

  
  

  - cannabis is a stressor because it increases the risk of schizophrenia up to 7x according to dose

  
  

  - this may be because cannabis interferes with the dopamine system

  
  

  - however most people don' t develop schizophrenia after taking cannabis because they don't have the vulnerability factors
• Treatment According to the interactionist Model

  - as the model acknowledges biological and psychological factors it combines both types of treatment

  
  

  - the model is associated with combing anti-psychotic drugs and psychological therapies e.g. CBT

  
  

  - in Britain it is increasingly standard practice to use a combination of antipsychotic drugs and CBT

  
  

  - in the US there is more conflict between the biological and psychological models of schizophrenia which has led to a slower adoption of the interactionist model

  
  

  - this means that drug treatment without psychological therapy is more common in the US
• Support for Vulnerability: Strength

  - (Tienari et al, 2004) investigated the impact of both genetic vulnerability and a psychological trigger (dysfunctional parenting)

  
  

  - 19,000 Finnish children whose biological mother shad schizophrenia were monitored

  
  

  - the genetic risk group was compared to the control group of adoptees who didn't have a family history of schizophrenia

  
  

  - adoptive parents were assessed for child-rearing style and it was found that high levels of criticism, hostility and low levels of empathy were associated with the development of schizophrenia
• Diathesis & Stress are Complex: Limitation

  - the original diathesis-stress model is oversimplified

  
  

  - multiple genes in multiple combinations influence diathesis and stress comes in many forms, including but not limited to dysfunctional parenting

  
  

  - diathesis can also be influenced by psychological factors and stress can be biological as well as psychological

  
  

  - (Houston et al, 2008) found child sexual abuse as a major influence on underlying vulnerability and cannabis was the major trigger

  
  

  - this means multiple factors affect diathesis and stress , supporting the modern model
• Real-World Application: Strength


  - an application of acknowledging both biological and psychological factors in schizophrenia has been combining drug and psychological therapy

  
  

  - studies have shown that using both enhances their effectiveness

  
  

  - (Tarrier al, 2004) randomly allocated 315 participants to either:

  . medication & CBT

  . medication & counselling

  . control group (medication only)

  
  

  - participants in the 2 combination groups showed lower symptoms than the medication only group following the trial

  
  

  - this means there is a clear practical advantage to adopting an interactionist approach to schizophrenia
• Real-World Application: Counterpoint


  - (Jarvis & Okami, 2019) point of saying successful treatment for a mental disorder justifies a particular treatment is the logical equivalent of saying because alcohol reduces shyness, shyness is caused by lack of alcohol

  
  

  - this logical error is called the treatment-causation fallacy

  
  

  - we cannot automatically assume the success of combined therapies means interactionist explanations are correct
• Urbanisation: Evaluation Extra


  - schizophrenia is more commonly diagnosed in urban rather than rural areas

  
  

  - this supports the interactionist position as it assumes that urban living is more stressful than rural, therefore city living acts a trigger

  
  

  - however it may simply be that schizophrenia is more likely to be diagnosed in cities

  
  

  - or people with diathesis for schizophrenia (e.g. teenagers abused as children) tend to migrate to cities