Interactionist approach

  • A broad approach to explaining schizophrenia which acknowledges that a range of factors, including biological and psychological factors, are involved in the development of schizophrenia

Test of difference Test of association or correlation

Unrelated design

Related desgin

Nominal data

Chi-squared

Sign test

Chi-squared

Ordinal data

Mann-whitney

Wilcoxon

Spearman’s rho

Interval data

Unrelated t-test

Related t-test

Pearsons r

Diathesis-stress model

  • Individual will develop schizophrenia if they have a biological predisposition and if they are exposed to stressful situations

  • Diathesis - predisposition to develop a medical condition

  • Stress - any environmental factor that could trigger the disorder

    • Need combination of both

Meehl’s 1962: original diathesis-stress model

  • Diathesis vulnerability is entirely genetic - result of a single “schizogene” which led to a biologically based “schizotypic” personality - extremely sensitive to stress

    • But polygenetic - over 100 different genes that may predispose one (combination of genes)

  • No amount of stress will lead to schizophrenia if gene not present

  • However chronic stress in one with the gene could lead to schizophrenia

Modern understanding

  • Diathesis not due to one “schizogene”. Many genes increase vulnerability

  • Doesn’t have to be genetic - early psychological trauma affecting brain development

    • E.g. Child-abuse affects the hypothalamic pituitary adrenal system

  • Stress is anything that risks triggering schizophrenia (including psychological stress)

  • E.g. Cannabis use can increase risk by up to seven times depending on dose - could be because it interferes with dopamine system

Application question:

  • She has a family history and therefore is likely to have some of the genes that can increase vulnerability for schizophrenia

  • Experienced multiple stresses like her dad dying and a big change - moving out

    • This could have therefore triggered the schizophrenia

Treatment according to interactionism

  • combination therapy - antipsychotic drugs and CBT

  • Turkington et al. - we can still believe that schizophrenia has a biological basis but use CBT to relieve the physical symptoms

  • UK - most common approach used

  • USA - conflict between biological and psychological therapies - medication alone more common

AO3

  • Support for dual role of vulnerability and stress - Tienari et al. (2004)

    • Study Design:

      • Conducted in Finland with 19,000 adoptees.

      • Compared individuals with a biological mother with schizophrenia (high genetic vulnerability) to those without such a family history (low genetic vulnerability).

    • Findings:

      • Schizophrenia was more likely to develop in individuals with high genetic vulnerability only if they were raised in a dysfunctional family environment (high stress).

      • In healthy family environments (low stress), even those with a genetic predisposition showed significantly lower rates of schizophrenia.

    • Conclusion:

      • Demonstrates the diathesis-stress model, where both genetic vulnerability (diathesis) and environmental stressors are required to trigger schizophrenia.

      • Neither genetic predisposition nor environmental stress alone is sufficient to cause the disorder

  • Usefulness of the interactionist approach in treatment

    • The interactionist approach underpins the use of combination therapies, such as antipsychotic medication (targeting biological factors) alongside psychological interventions like CBT or family therapy (addressing environmental/stress factors).

    • This integrated method often proves more effective than single treatments.