Interactionist approach to schizophrenia:

Question 1

✅[DIATHESIS STRESS MODEL]: RESEARCH SUPPORTING BOTH GENETIC AND ENVIRONMENTAL FACTORS:

Answer 1

• Gottesman (1991) reviewed cases of schizophrenia and found a concordance rate of 48% for monozygotic (MZ) twins, who share 100% of their DNA, compared to 17% for dizygotic (DZ) twins. This is significantly higher than the general population rate of 1%.
• This suggests that while genetic factors play a major role, they cannot fully explain schizophrenia because the concordance rate for MZ twins is not 100%. This indicates that environmental or psychological experiences must trigger the disorder in one twin but not the other.
• This evidence highlights the importance of the diathesis-stress model, as it accounts for both biological and environmental influences, improving the validity of the interactionist approach. However, twin studies may have issues with generalisability, as shared environments could also inflate concordance rates.

Question 2

✅[DIATHESIS-STRESS MODEL] EVIDENCE OF EFFICACY OF COMBINED TREATMENT:

Answer 2

• Tarrier et al. (2004) found that the most effective treatment combines drug therapy with psychological interventions such as CBT. Patients who received both therapies showed significantly lower levels of schizophrenia symptoms compared to those receiving either treatment alone.
• This research highlights that the interactionist approach achieves better treatment outcomes because it addresses both biological and psychological aspects of the disorder. By targeting multiple factors contributing to schizophrenia, this approach provides a more comprehensive and holistic form of care.
• This is significant because it improves reliability and generalisability to real-world applications, as it can be tailored to individual patient needs. However, the interactionist approach may have practical limitations, such as increased costs and the need for multidisciplinary teams, which could impact its accessibility in all healthcare settings.

Question 3

❌ ORIGINAL DIATHESIS-STRESS MODEL IS OVERLY SIMPLISTIC:

Answer 3

• This is because vulnerability to schizophrenia is influenced by multiple genes, each with a small effect, rather than a single “schizogene.” Additionally, stress comes in many forms and is not limited to psychological factors like a schizophrenogenic mother.
• Researchers now recognise that biological factors can also act as stressors. For instance, Houston et al. (2008) found that childhood sexual trauma acted as a diathesis, while cannabis use served as a trigger for schizophrenia.
• This highlights that the original diathesis-stress model was reductionist in viewing diathesis as purely biological and stress as purely psychological. The revised understanding provides a more comprehensive and nuanced explanation, improving its validity but also indicating that the model may need further refinements to account for the complexity of these interactions.