interactionist approach to schizophrenia

• The diathesis-stress model suggests both a vulnerability and a trigger is needed to develop SZ. Meehl argued that someone without the 'schizogene' should never develop SZ no matter how much stress they were exposed to. A person with the gene is vulnerable to the effects of chronic stress. The schizogene is necessary but not sufficient for the development of SZ
• The modern understanding of the diathesis stress model is that SZ isn't due to a single gene but many genes. It also doesn't have to be genetic as it could be early psychological trauma affecting brain development. A modern definition of stress in relation to diathesis-stress includes anything that risks triggering SZ. This can be psychological or biological
• Cannabis can increase the risk of SZ up to 7 times because it interferes with the dopamine system
• Antipsychotic drugs can be taken in combination to CBT as treatment according to the interactionist approach. In Britain it is a standard practice to do this. In US there is more conflict between psychological and biological models of SZ and so this has led to slower adoption of the interactionist approach
• One strength is support for the dual role of vulnerability and stress. Tienari et al. studies children adopted away from mothers diagnosed with SZ. The adoptive parents' parentage styles were assessed and compared with a controlled group of adoptees with no genetic risk. A chip rearing style with high levels of criticism and conflict and low levels of empathy was implicated in the development of SZ but only for children with a high genetic risk. This shows that a combination of genetic vulnerability ad family stress leads to increased risk of SZ
• One limitation of the original diathesis stress model is that it is over simplistic. Multiple genes increase vulnerability, each with a small effect on its own. Stress comes in many forms, including dysfunctional parenting. Researchers now believe stress van also include biological factors. For example, Houston et al. found childhood sexual trauma was a diathesis and cannabis use was a trigger. This means that there are multiple factors, biological and psychological affecting both diathesis and stress
• One strength of interactionist approach is real world application. Tarrier et al. randomly allocated 315 participants to medication and CBT group, medication and supportive counselling group or control group (medication only). Participants on the 2 combination groups showed lower symptom levels that those in control group but no difference in hospital readmission. This means that there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes.