Interactionist approach 5

Considers that there are biological (genetic vulnerability, neurochemical/neurological abnormality), psychological (stress from life events and daily hassle, poor interactions in their family) and societal factors in the development of schizophrenia. 

The diathesis-stress model: 

Diathesis =vulnerability. 

Stress in this context is a negative psychological experience. 

It says that both a vulnerability to schizophrenia and a stress-trigger are necessary for the condition to develop.  

Meehl’s model: 

In the original model, diathesis was entirely genetic and the result of a single schizogene. 

This led to the development of a biologically based schizotypic personality. One characteristic is sensitivity to stress.  

According to Meehl if a person doesn’t have the schizogene then no amount of stress would lead to schizophrenia. 

However, in carriers of the gene, chronic stress through childhood and adolescence e.g a schizophrenogenic mother could result in the development of schizophrenia. 

The modern understanding 

The modern understanding of diathesis 

It is now believed that many genes increase genetic vulnerability and that there is no single schizogene. 

Include a range of factors beyond genes such as psychological trauma-so trauma becomes the diathesis rather than the stressor. 

Read et al proposed a neurodevelopmental model in which early trauma affects the developing brain e.g the Hypothalamic-pituitary adrenal (HPA) system can become overactive, making the person much more vulnerable to later stress. 

The modern understanding of stress 

In the original model stress was seen as psychological in nature e.g parenting. 

The modern definition includes anything that risks triggering schizophrenia (Houston et al). 

Recent research has shown cannabis use can trigger an episode of schizophrenia as it is seen as a stressor as it interferes with the dopamine system and increases the risk of schizophrenia by up to seven times. However, most people do not develop schizophrenia after smoking cannabis so there may be one or more vulnerability factors. 

Treatment according to the interactionist model: 

The interactionist model of schizophrenia considers both biological and psychological factors so is compatible with both biological and psychological treatments. 

Antipsychotic medication and CBT are combined.  

Turkington et al pointed out that it is possible to believe in biological causes of schizophrenia and still practice CBT to relieve psychological symptoms. 

However, it is not possible to adopt a purely biological approach and to simultaneously treat them with CBT.  

Evaluation: 

Support for the effectiveness of combinations of treatment-Nicholas Tarrier et al randomly allocated 315 patients to a medication and CBT group, medication and supportive counselling or a control group. Patients in the two combination groups showed lower symptom levels than those in the control group (medication only). There was no difference in rates of hospital readmission.f 

Evidence for the role of vulnerability and triggers-Tienari et al found that child-rearing style characterized by high levels of criticism and low levels of empathy was implicated in the development of schizophrenia but only for the adopted children who had a high genetic risk and were adopted by Finnish mothers with schizophrenia but not in the adopted control group with no genetic risk. YES