Interactionalist explanations

• The interactionist approach suggests the development of schizophrenia is due to the combined effects of the environment and biological factors.
• The diathesis-stress model is a psychological concept that a disorder is due to the interaction between a predisposed vulnerability and an environmental trigger later in life.
• The diathesis in schizophrenia is often considered the genetic vulnerability (eg - the dopamine imbalance). Many researchers also consider non-genetic diathesis, such as a pregnant mother having a birth complication or very early child abuse thought to influence the creation of a diathesis.
• Stressors in schizophrenia are later negative environmental experiences such as family dysfunction, emotional stress / anxiety or a major life event.
• Strengths of the interactionist approach:

  • Supporting research - Gottesman reviewed cases of schizophrenia and found a concordance rate of 48% for MZ twins and 17% for DZ twins. This compares to the general population of 1%. This suggests a role for both biological factors, as the concordance rate is much higher for identical twins, as well as an environmental factor, as the concordance rate is less the 100% suggesting an alternative psychological trigger.
• Strengths of the interactionist approach:

  • Adoption studies by Tienari.
• The interactionist approach suggests both a biological and psychological aspect to the treatment of schizophrenia, combining both CBT with drug therapies.
• Limitations of the interactionist approach:

  • Limited explanation - The mechanism by which a negative psychological event actually triggers a complex biological response resulting in symptoms is still uncertain, reducing the confidence in the interactionalist approach as a full explanation for schizophrenia.
• Limitations of the interactionalist approach:

  • Original diathesis-stress model is considered as an over-simplified explanation and a reflection of the outdated understanding of that disorder. Ripke demonstrated that there are over 108 candidate genes, each slightly increasing the risk of SZ, and so there is no single ‘schizogene’. Stress can come in many forms, so the diathesis is not exclusively biological, nor is the stressor exclusively psychological. This may also be considered a strength in the sense that our current understanding of SZ is far more accurate than the original perspective.