Interactionist Approach

• •This approach to schizophrenia acknowledges the that a range of biological, psychological and societal factors are involved in the development of schizophrenia.•A diathesis-stress model is an interactionist approach to schizophrenia. Schizophrenia is argued to be the result of both an underlying (genetic) vulnerability (diathesis) and an environmental trigger (stress). Both are necessary for the onset of schizophrenia.
• Diathesis-stress model

  Genetic vulnerability + Negative psychological experience = Schizophrenia
• The diathesis (vulnerability) for schizophrenia is entirely genetic
• Genes are assumed to cause neurochemical abnormalities that in turn, result in an increased risk for schizophrenia
• If a person does not have the genetic vulnerability, no amount of stress would lead to schizophrenia
• Stress

  Negative psychological experience e.g. dysfunctional parents and stressful live events (e.g. going to university, moving house etc.)
• Chronic stress in someone who carries the genetic vulnerability could result in schizophrenia
• Diathesis and stress

  Add together in some way to produce schizophrenia (additive)
• Supporting Evidence

  • Gottesman (1991) conducted a large-scale family and found much higher concordance rates in MZ twins (48%) in comparison to DZ twins (17%)
• Individuals with identical genetic make-up (MZ twins)


  Have an increased risk of developing schizophrenia compared to those who share fewer genes
• This supports the genetic explanation of schizophrenia as there is an association between the degree of genetic similarity and shared risks of schizophrenia
• In just over 50% of identical twins in which one twin was diagnosed with schizophrenia, the other doesn't meet the criteria for the disorder
• This discordance amongst people who share 100% of their genes indicates that environmental factors must also play a role in determining whether a biological vulnerability for schizophrenia develops into disorder
• Treatment According To Interactionists

  •As the interactionist model acknowledges both biological and psychological factors in schizophrenia, it is associated with combining antipsychotic medication and psychological therapies (most commonly CBTp).
• Tienari et al. (2004)


  Study that compared 145 children who had at least one biological parent with schizophrenia and were adopted into a new family with 158 adoptees without this genetic risk
• Study procedure

  1. Adopted parents were assessed for child-rearing style

  2. Rates of schizophrenia across the two groups was compared
• They found that a child-rearing style characterised by high levels of criticism and conflict and low levels of empathy were implicated in the development of schizophrenia, but only for those in the high-genetic-risk group
• High-genetic-risk adoptees reared in families with low scores on this child-rearing style scale


  Were significantly less likely to have developed schizophrenia than high genetic risk adoptees reared in families with high scores on the child-rearing style scale