interactionist approach: diathesis-stress model

what is the diathesis stress model?

SZ is an interaction of biological and environmental influences

what is an example of environmental and biological influences in SZ?

• family and twin studies suggest that people have avrying levels of genetic vunderability to SZ

• whether a person actually develops SZ is also due to the amount and levels of stress over their lifetime

what research shows that SZ has a genetic component?

adoption study of tienari et al

what did tienari et al show?

increases risk of developing SZ from biological rather than social factors

what contrasts that genetic influences play a role?

joesph - concordance rates were only 40% for MZ twins

indicating that environmental factors must play a part

what are environmental stressors?

childhood trauma, stress of highly urbanised living

what did Varese et al do?

• children who experienced trauma under the age of 16 were 3 x more likely to develop SZ later in life compared to the general population

• Sz occurence was positvely correlated to the level of the trauma

what is the evaluation of the interactionist approach?

• oversimplistic

• supporting evidence

• supporting evidence of effective treatment

• treatment aetiology fallacy

• time consuming and expensive

how is the diathesis stress model oversimplisitc?

• single gene combinded with SZ parenting styles

• very little evidence in parenting

• geentic vunderability is also more complex than single genes

what is supporting evidence?

tienari et al

what is supporting evidence for the effectiveness of interactionist treatments?

• anderson et al - less than 5% relapse rates when used drugs and family therapy

• tarrier et al - more effective than drugs alone and showed fewer symptoms when CBT and drugs

• token economies - Upper and newton - weight gain associated with antipyschotics and adressed with token economy

what is treatment aetiology fallacy?

that the success of interactionist treatments doesnt mean that the interaction caused the condition in the first place