Schizophrenia - The Interactionist Approach

Question 1

The Interactionist Approach

Answer 1

• This approach to schizophrenia acknowledges the that a range of biological, psychological and societal factors are involved in the development of schizophrenia.
• A diathesis-stress model is an interactionist approach to schizophrenia. Schizophrenia is argued to be the result of both an underlying (genetic) vulnerability (diathesis) and an environmental trigger (stress). Both are necessary for the onset of schizophrenia.

Question 2

Meehl’s (1962) Diathesis Stress Model

Answer 2

• The diathesis (vulnerability) for schizophrenia is entirely genetic. Genes are assumed to cause neurochemical abnormalities that in turn, result in an increased risk for schizophrenia.
• If a person does not have the genetic vulnerability, no amount of stress would lead to schizophrenia.
• The stress (trigger) for schizophrenia is negative psychological experience e.g. dysfunctional parents and stressful life events (e.g. going to university, moving house etc.).
• Chronic stress in someone who carries the genetic vulnerability could result in schizophrenia.
• It is thought that diathesis and stress add together in some way to produce schizophrenia (additive).

Question 3

Gottesman (1991) in evidencing the diathesis stress model

Answer 3

• Gottesman (1991) conducted a large-scale family and found much higher concordance rates in MZ twins (48%) in comparison to DZ twins (17%).
• This supports that individuals with identical genetic make-up (MZ twins) have an increased risk of developing schizophrenia compared to those who share fewer genes, supporting the genetic explanation of schizophrenia as there is an association between the degree of genetic similarity and shared risks of schizophrenia.
• However, in just over 50% of identical twins, the other doesn’t meet the criteria for the disorder. This discordance amongst people who share 100% of their genes indicates that environmental factors must also play a role in determining whether a biological vulnerability for schizophrenia develops into disorder.

Question 4

Tienari et al (2004)

Answer 4

• 145 children who had at least one biological parent with schizophrenia were adopted into a new family and were compared with 158 adoptees without this genetic risk. The adopted parents were assessed for child-rearing style and the rates of schizophrenia across the two groups was compared.
• They found that a child-rearing style characterised by high levels of criticism and conflict and low levels of empathy were implicated in the development of schizophrenia, but only for those in the high-genetic-risk group.
• High-genetic-risk adoptees reared in families with low scores on this child-rearing style scale were significantly less likely to have developed schizophrenia than high genetic risk adoptees reared in families with high scores on the child-rearing style scale.

Question 5

Treatment in accordance to the interactionist approach

Answer 5

• As the interactionist model acknowledges both biological and psychological factors in schizophrenia, it is associated with combining antipsychotic medication and psychological therapies (most commonly CBTp).

Question 6

Evaluating the interactionist approach to schizophrenia - Strengths

Answer 6

1) There is evidence to support the dual role of genetic vulnerability and stress in the development of schizophrenia - Tienari et al’s study
- This suggests that both genetic vulnerability and family-related stress are important to the development of schizophrenia - genetically vulnerable children are more sensitive to parenting behaviour, and this is strong direct support for the importance of adopting an interactionist approach to schizophrenia, including that poor parenting is a possible source of stress

2) There is support for the usefulness of adopting an interactionist approach from studies comparing the effectiveness of combinations of biological and psychological treatments for schizophrenia vs biological treatments alone
- Tarrier et al (2004) randomly allocated 315 patients to a medication + CBTp group, or a medication group + supportive counselling group, or a control group (just medication), and they found that patients in the two combination groups showed lower symptom levels than those in the control group, although there was no difference in rates of hospital readmission
- This suggests a clear practical advantage to adopting an interactionist approach in the form of superior treatment outcomes and therefore highlighting the importance of taking an interactionist approach

Question 7

Evaluation of the interactionist approach to schizophrenia - Weaknesses

Answer 7

1) Diatheses may not be exclusively genetic and stress may involve anything that risks triggering schizophrenia
- The increased risk of schizophrenia can also result from brain damage caused by environmental factors - Verdoux et al (1998) estimated the risk for developing schizophrenia later in life was 4 times greater for those who had experienced prolonged labour and oxygen deprivation than those without said complications. Additionally, cannabis may be a stressor as it increases the risk of schizophrenia by up to 7x depending on the dose, likely because cannabis interferes with the dopamine system
- This suggests the idea of the old diathesis-stress model may be overly simple but it still supports the interactionist approach to schizophrenia is important in that vulnerabilities and triggers seem add together in some way and produce schizophrenia - although most people do not develop schizophrenia after smoking cannabis and so it may only be one of many triggering factors in stress, the model is therefore poor at predicting exactly who will develop schizophrenia

2) It is possible that stressors earlier in life can also influence how people respond to later stressful events, and increase their susceptibility to the disorder - maladaptive methods of coping with stress in childhood and throughout development means that the individual fails to develop effective coping methods which in turn compromises their resilience and increases vulnerability, resulting in a more stressful life for the individual and triggering schizophrenia
- Therefore, it is extremely difficult to determine the causal stress that triggered schizophrenia which may negatively impact the effectiveness of treatment