Interactionist approach - schizophrenia

diathesis-stress model - schizophrenia

Result of an interaction betwee biological and environmental influences

Meehl's old diathesis stress model

Schizophrenia thought to be result of single schizogene, combined with chronic stress, in particular schizophrenic mother. Meehan believed that if a person did not have the schizogene, then no amount of stress would lead to schizophrenia. Must be a combo of nature and nurture.

Modern diathesis stress model

Schizophrenia is polygenetic. Trauma can also affect the developing brain. Family issues are a type of influential stress, but the modern definition of stress included anything that risks triggering schizophrenia

Research proposed a model in which early trauma can alter _ and make an individual more vulnerable to ____

Neurodevelopmental, the developing brain, later stress

Recent research suggests that what factor can increase risk of schizophrenia by how much? In what situation?

Cannabis can increase risk up to 7x, when smoked in high doses, and in people with pre-existing genetic vulnerability.

Why does cannabis increase schizophrenia risk?

Interferes with dopamine system

Name of key study

Tienari et al

Tienari et al participants and details.

164 adoptee offspring of women who had been admitted to finish psychiatric hospitals 1960-78, who had been diagnosed with schizophrenia at some point (high risk group.

Matched with 197 adoptees without genetic risk (low risk group)

Tienari et al procedure

Both groups independently assessed after interval of 12 years, with follow up after 21 years. Psychiatrists also assessed family functioning in the adoptive families using a scale - the Oulu Family Rating Scale (OPAS scale). The interviewing psychiatrists were kept blind as to whether the biological mother was schizophrenic or not.

Oulu family rating scale

measures families on various aspects of functioning such as parent-offspring conflict, lack of empathy and insecurity

Tienari et al findings and conclusions

of the 303 adoptees, 14 developed schizophrenia over the course of the study. 11 of these were from the high risk group, and 3 from the low risk group.

However, being reared in a 'healthy' adoptive family appeared to have a protective effect for those that had a high genetic risk.

family stress was a significant predictor of the development of schizophrenia in the adoptees that had a high risk of schizophrenia.

This is because they found that a child rearing style with high levels of criticism and conflict and low levels of empathy appeared to be associated with developing schizophrenia, but only for the children with high genetic risk.

Tienari - holistic strength so valid

Considered nature and nurture enabling explanation to be more accurate, since they can't be separated, so both contribute to schizophrenia.

Tienari - application

Since it concludes nature and nurture contribute, can combine treatments to be more effective EG family therapy to reduce stressors and antipsychotics to combat biological.

Tienri application - tarrier et al

found that people with schizophrenia receiving 20 sessions of CBT in 10 weeks, coupled with drug therapy, followed by four booster sessions during the next year, had a better reduction in symptoms than sufferers receiving drug therapy alone.

The Tienari research supports what model?

Diathesis stress model

Does interactionist approach take a nomothetic or idiographic approach? Why is this bad?

Nomothetic - Not everyone who has a certain combination of genes and stressors will develop schizophrenia. All research simply suggests an increased vulnerability. Therefore, may not be a complete explanation for all individuals with schizophrenia. In the research by Tienari, not all participants who had a genetic vulnerability and a negative family environment, developed schizophrenia. Maybe there are dispositional explanations which have not been considered by the interactionist explanation.

Weakness of Tienari - procedure/ validity issues

study failed to reflect developmental changes in family functioning over time, as they only completed the OPAS scale once. They also acknowledge that observing reciprocal interactions between the adoptive family and the adoptees makes it impossible to determine how much of the stress observed is assigned to the family and how much is actually caused by the adoptee him or herself.

Research to support effectiveness of an interactionist treatment

Tarrier et al - randomly allocated patients to either a medication plus CBT group, a medication plus supportive counselling group and a control group who just took medication. They found that patients in the two combination groups showed lower levels of symptoms than those in the control group. This is a clear benefit of the interactionist approach because it shows that it targets more symptoms when using a combination approach and this will help to improve the quality of life for the patient. In addition, by taking a combination approach, you can avoid issues such as the treatment causation fallacy.

Treatment-causation fallacy

This is the assumption, that when using one treatment such as drugs, if symptoms are reduced, it is assumed that the cause is biological. The same applies to CBT, because if symptoms are reduced, it is assumed to have a cognitive cause. However, it might be too simplistic to make this assumption

Simplistic benefit of using an interactionist treatment

By using an interactionist treatment, it ensures all bases are covered by targeting cognition, behaviour and biology, which will hopefully lead to a more successful treatment.

Alternative explanation to interactionist

not all children developed schizophrenia when faced with a genetic vulnerability, and negative child rearing. This suggests that other factors need to be considered. For example, the influence of dispositional factors such as personality types may also play a role in explaining schizophrenia.

Typical antipsychotics example

chlorpromazine

atypical antipsychotics example

Clozapine

How many sessions does CBT take?

5-20