Interactionist explanations

• The interactionist approach to explaining schizophrenia outlines a diathesis stress model.

  The diathesis is a vulnerability and Menis Model suggests you inherit a schizogene and have a biological based schizotypic personality which makes you sensitive to stress.

  If the gene wasn’t present then there would be no schizophrenia regardless of stressors but chronic stress like the Sz mother may trigger the gene.
• The stress is usually an internal or external factor that triggers a vulnerability.

  Historically a traumatic childhood, expressed emotion or a schizophrenic mother may have triggered the diathesis to develop schizophrenia.

  Now cannabis has been implicated and found to increase the likelihood of schizophrenia by 7 times as it interferes with dopaminergic systems.
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  Research to support this comes from Tiernari et al who followed 19,000 adopted Finish children who had diagnosed biological mothers, they compared these to an adopted control group.

  They also assessed the adoptive parents for expressed emotion e.g. high levels of hostility and low levels of empathy.

  They found that only the genetic risk group developed schizophrenia suggesting those with a predisposition and family trauma are more likely to develop schizophrenia which supports the approach and increases validity.
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  Further research support comes from Brustowicz et al who found early trauma that threatened the physical, emotional and sexual integrity of an individual at or younger than 19 was significantly associated with the expression of schizophrenia within families.

  This therefore provides evidence for the diathesis stress and increases the validity.
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  Issues with this is there are alternative explanations.

  For example Ripke found 108 candidate genes showing it is a polygenic condition and not a single schizogene influencing the development.

  Read et al proposed that the neurodevelopmental model where trauma affects brain development makes a person more vulnerable to later stress e.g child abuse can cause the hypothalamus pituitary adrenal system to be overactive.

  Therefore this suggests perhaps the approach is not as valid as first thought.