Strength:
-Evidence for the role of vulnerability and triggers, Tienari et al adoption study of Finnish mothers with Sz and a control group without vulnerability. Genetically vulnerable children are more sensitive to parenting behaviour. this is strong support for the diathesis-stress model.
-Support for the effectiveness of combinations of treatments, Tarrier et al, 315 patients 3 groups, control, medication+CBT, Medication+supportive counselling. Both groups with combinations had success in reducing symptoms however no reduction in readmission to hospital.
Weakness:
-The original diathesis stress model is oversimplified, the classic model which includes the "schizo gene" has been suggested to be too simple as it's now believed that many genes all have a part in causing Sz