An interactionist approach

• Diathesis-stress model - mental disorder is the result of an interaction between biological (diathesis) & environmental (stress) influences
• Diathesis in schizophrenia interactionist approach:

  • MZ twins have a 40% concordance rate, DZ twins have a 7%
  • Shows that there's a genetic component
  • Concordance rate is not 100% so there must be another factor
• Stress in schizophrenia interactionist approach:

  • Childhood trauma or living in a highly urbanised area
  • Children who experienced severe trauma were 3x more likely to develop schizophrenia
• Interactionist approach for schizophrenia key study:

  • Tienari et al
  • 145 adopted children of biological mothers with schizophrenia & 158 adoptees without this risk
  • Assessed after 12 & 21 years
  • Adoptive families were assessed using the OPAS scale which measures family functioning ( e.g. conflict, lack of empathy )
  • Findings: 14 developed schizophrenia, 11 had schizophrenic mothers
  • Healthy adopted family had protective effect, disturbed family likely to trigger schizophrenia
• Interactionist approach for schizophrenia AO3:

  • ❌ Diatheses may not just be genetic - complications at birth can create a 4x risk
  • ❌ Difficulties in determining causal stress - maladaptive coping methods in childhood increases vulnerability
  • ❌ Limitations of the Tienari study - assessed family functioning at one point in time - doesn't reflect developmental changes, can't determine if it's the family or the adoptees that cause the stress
  • ✅ Implications for treatment - cytomegalovirus interacting with deficit gene and causing schizophrenia suggests use of antiviral medication during pregnancy