L8: Interactionist Approach to Sz

Question 1

Diathesis stress model

Answer 1

• Interactionist approach
• explains that mental disorders are as a result of biological (diathesis) and psychological (stressors) factors.
• both vulnerability and stress trigger schizophrenia.

Question 2

Original thinking: Meehl’s model

Answer 2

• Meehl’s model was entirely genetic, due to a single schizogene.
• Meehl argues that someone without the schizogene should never develop schizophrenia, no matter how much stress they’re exposed to.
• But a person who does have the gene is vulnerable to the effects of chronic stress (schizophrenogenic mother).

Question 3

Modern understanding of diathesis stress model:

Answer 3

• schizophrenia has a genetic component. Mz twins (17%) concordance rates are greater than Dz twins (48%)
• However, Mz concordance rates are still less than 50% which suggests that environmental factors must play a part.
• It is believed that many genes increase vulnerability (schizophrenia is polygenic and Aetiologically heterogeneous)
• Diathesis (biological) does not have to be genetic, it can be early psychological trauma (affects brain development)
• child abuse affects the hypothalamic-pituitary-adrenal sysetm, making the child vulnerable to stress.

Question 4

Modern understanding of stress - cannabis

Answer 4

• Anything that risks triggering schizophrenia
• A lot of research looks at cannabis as cannabis is a stressor that can increase schizophrenia by up to 7x as cannabis interferes with the dopamine system.

However, not everyone who uses cannabis develops schizophrenia, so it seems there must be other vulnerability factors.

Question 5

Modern understanding of stress: urban area

Answer 5

further findings suggest living in densely populated areas increase the risk of developing schizophrenia.
Vassos (12) urban areas over 2x more likely to develop schizophrenia.

Question 6

Treatment, Interactionist:

Answer 6

Turkington (06) suggests that it is not possible to adopt an entirely biological approach, tell patients their condition is entirely biological then treat them with CBT.

We cannot adopt a purely biological approach and say the cause is due to chemical imbalances then treat with CBT, the two must interact. We can’t adopt a purely biological approach and say the cause is due to chemical imbalances then treat with CBT, the two must interact.

Question 7

Treatment combinations

Answer 7

Antipsychotics + Anti-depressants = to treat negative symptoms.

Antipsychotics + family therapy = cure dysfunctional family problems.

Antipsychotics + CBT = to treat negative and positive symptoms.

Question 8

AO3 NEGATIVE

Answer 8

• Multiple genes increase vulnerability, each with a small effect on its own, there is NO schizogene. Stress comes in many forms, Houston (08) found childhood sexual trauma was a diathesis and cannabis use a trigger. This demonstrates the original diathesis- stress model is too simplistic.
• There is strong evidence to suggest that some sort of underlying vulnerability coupled with stress can lead to schizophrenia. But we don’t understand the mechanisms by which symptoms of schizophrenia appear and how both vulnerability and stress produce them. This does not undermine support for the approach, but it means we have an incomplete understanding of the actual mechanism. We don’t know how diathesis and stress work.

Question 9

AO3: STRENGTHS

Answer 9

+ Hogarty (86) looked at relapse rates of schizophrenia patients: drug therapy alone had a relapse rate of 41% but combined with family therapy relapse rates decreased to 19% and with social support therapy 20%. Cheaper in the long run as it reduces hospitalisation.

+ erai et al (2004) show that combination of genetic vulnerability and family stress leads to an increased risk of Sz. Also show there is a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes.