Sc - An interactionist approach

Question 1

Diathesis-stress model

Answer 1

Explains mental disorders as the result of an interaction between biological (the diathesis) and environmental (stress) influences.

Question 2

Diathesis to explain SZ

Answer 2

SZ has a genetic component in terms of vulnerability.

Question 3

What findings provide evidence for diathesis to explain SZ?

Answer 3

Findings that the identical twin of a person with SZ is at greater risk of developing SZ than a sibling of fraternal twin, and that adoptive relatives do not share the increased risk of biological relatives (Tienari et al., 2004).

Question 4

How do twin studies provide evidence that the environment (stress) also plays a role in developing SZ?

Answer 4

In about 50% of identical twins in which one twin is diagnosed with SZ, the other never meets the diagnostic criteria for the disorder.

This discordance among identical twins indicates that environmental factors must also play a role in determining whether a biological vulnerability for SZ actually develops into the disorder.

Question 5

What sort of stressful life events can trigger SZ?

Answer 5

Variety of forms such as childhood trauma or the stresses associated with living in a highly urbanised environment.

Question 6

What evidence did Varese et al. (2012) find about environmental stress?

Answer 6

Children who experienced severe trauma before the age of 16 were 3 times as likely to develop SZ in later life compared to the general population.

There was a relationship between the level of trauma and the likelihood of developing SZ, with those severely traumatised as children being at greater risk.

Question 7

How does urbanisation link to SZ?

Answer 7

Research has suggested that a high level of urbanisation is associated with increased risk of developing a range of different psychoses, including SZ.

Question 8

What did a meta-analysis of Vassos et al. (2012) find?

Answer 8

That the risk for SZ in the most urban environments was estimated to be 2.37 times higher than in the most rural environments.

Question 9

What is thought to be the reason behind urbanisation being linked to SZ?

Answer 9

It is possible that the more adverse living conditions of densely populated urban environments may be a contributory factor.

Question 10

What factor might the relationship between urban stress and SZ be conditional on?

Answer 10

A pre-existing genetic risk for the disorder or some other biological vulnerability for SZ.

Question 11

What are the ways in which a combination of diathesis and stress can lead to the onset of SZ?

Answer 11

For example:

Relatively minor stressors may lead to the onset of the disorder for an individual who is highly vulnerable.

Or, a major stressful event might cause a similar reaction in a person low in vulnerability.

Question 12

Name some environmental (stress) influences that may contribute to the risk of developing SZ?

Answer 12

Urbanisation and childhood trauma.

Question 13

What does the idea that a combination of diathesis and stress can lead to the onset of SZ pre-suppose?

Answer 13

Additivity, i.e. that diathesis and stress add together in some way to produce the disorder.

Question 14

What is the key study for an interaction approach to SZ?

Answer 14

Tienari et al. (2004)

Question 15

What did the Tienari et al. (2004) study test?

Answer 15

The hypothesis that genetic factors moderate susceptibility to environmental risks associated with adoptive family functioning.

Question 16

Procedure of the Tienari et al. (2004) study of the interactionist approach for SZ

Answer 16

• Hospital records reviewed for nearly 20,000 women admitted to Finnish psychiatric hospitals between 1960 and 1979, identifying those who had been diagnosed at least once with schizophrenic or paranoid psychosis.
• The list was checked to find those mothers who had one or more of their offspring adopted away.
• The resulting sample of 145 adopted-away offspring (the high-risk group) was then matched with a sample of 158 adoptees without this genetic risk (the low-risk group).
• Both groups of adoptees were independently assessed after a median interval of 12 years, with a follow-up after 21 years.
• Psychiatrists also assessed family functioning in the adoptive families using the OPAS (Oulu Family Rating Scale). This scale measures families on various aspects of functioning such as parent-offspring conflict, lack of enthalpy and insecurity.
• The interviewing psychiatrists were kept blind as to the status of the biological mother (i.e. SZ or no SZ).

Question 17

Findings of the Tienari et al. (2004) study of the interactionist approach for SZ

Answer 17

• Of the 303 adoptees, 14 had developed SZ over the course of the study.
• Of these 14, 11 were from the high-risk group (i.e. those with mothers previously diagnosed with SZ or paranoid psychoses) and 3 were from the low-risk group (i.e. the control group adoptees).
• However, being reared in a ‘healthy’ adoptive family (low OPAS ratings) appeared to have a protective effect even for those at high genetic risk for SZ.
• High-genetic-risk adoptees rearing in families with low OPAS ratings were significantly less likely to have developed SZ than high-genetic-risk adoptees reared in families with high OPAS ratings.
• In adoptees at high genetic risk of SZ, but not in those at low genetic risk, adoptive-family stress was a significant predictor of the development of SZ.