interactionist approach

• interactionist approach:

  the view that both nature and nurture work together to shape human behaviour

  
• the diathesis stress model:

  highlights the significance of environmental factors and biological factors

  explains that individuals will develop Sz if they have a biological predisposition and if they are exposed to stressful situations

  
• diathesis

  the findings from identical twins supports the idea of a genetic component in terms of vulnerability

  an identical twin of a person with Sz is at greater risk of developing Sz than a sibling or Dz twin

  however concordance rates are only around 48%

  this indicates that environmental factors must also play a role in determining whether a biological vulnerability for Sz actually develops into the disorder
• stress


  stressful life events may be able to trigger Sz, can be a variety of forms like childhood trauma or everyday stressors from a highly urbanised life

  research suggests that a high level of urbanisation is associated with an increased risk of developing a range of different psychoses

  Vassos et al: meta-analysis found that the risk of Sz in the most urban environments were estimated to be 2.37 times higher than in the most rural areas

  relationship: urban stress + Sz is conditional on some other factor, a pre-existing genetic risk for the disorder as well as family dysfunction
• high and low vulnerability

  
• Tienari et al (2004)

  hypothesis: genetic factors moderate susceptibility to environmental risks associated with adoptive family functioning

  sample: mothers with Sz who have had children adopted away - 145 adopted away offspring (high risk group)

  matched with 158 adoptees without genetic risk (low risk group)

  procedure: both groups of adoptees were independently assessed after 12 years and then followed up 21 year later

  psychiatrists family functioning using OPAS which measures families on various aspects such as conflict, lack of empathy and insecurity
• tienari

  findings: of the 303 adoptees, 14 developed Sz - 11 were from the high risk group and 3 low risk group, being reared in a healthy adoptive family with low OPAS rating seemed to have a protective effect even those at high genetic risk

  high genetic risk + low OPAS were significantly less likely to have developed Sz

  conclusion: in adoptees at high genetic risk of Sz adoptive family stress was a significant predictor of the development of Sz

  when assessed, only assessed at one point in time which fails to reflect developmental changes in family functioning over time
• evaluation:

  diathesis may not be exclusively genetic

  it emphasises vulnerability in terms of genetic influences alone but this can increase the risk of brain damage caused by environmental factors

  Verdoux et al (1998) the risk of developing Sz from complicatios at birth is four times greater

  importance of the approach: support for the usefulness of the combination of drugs and CBT, patients showed lower symptoms and the approach is more cost-effective

  interactive treatment (drugs and CBT) are needed for effective treatment
• evaluation:

  too simplistic/reductionist

  the idea that a single gene combined with a certain parenting style cause the Sz is too simplistic

  multiple genes have been found to increase the risk of developing the illness indicating that there is no single- schizogene

  not limited to just parenting style and family dynamics

  a holistic and interactionist approach to understanding the onset of Sz is needed, idiographic research should be conducted and personalised triggers found

  Cannabis is a stressor and increases the risk of Sz by seven times