What is Diathesis-stress model in IB Psychology?

Diathesis-stress model is a key topic in IB Psychology covering core concepts, theories, and research relevant to the IB Psychology syllabus, examined in Paper 1 and Paper 2.

How is Diathesis-stress model assessed in IB Psychology?

Diathesis-stress model is assessed in Paper 1 Section A and B and may appear in Paper 2. Understanding the mark scheme is essential for scoring full marks.

How do I write a high-scoring answer on Diathesis-stress model?

A high-scoring answer requires a clear command term response, relevant theory with supporting evidence, critical evaluation, and a conclusion.

IB Psychology Diathesis-stress model Notes

Study Notes

Mark Scheme

SECTION A MARK SCHEME (4 marks) Must Include: • Diathesis: biological vulnerability/genetic predisposition • Stress: environmental trigger/stressor • Threshold concept: both needed to exceed threshold • Interactionist framework (nature + nurture) • Named condition (e.g. schizophrenia) • Specific stressor example (e.g. cannabis use, urban environment) • Show why either alone is insufficient

Link Formula: "[Condition] results from [genetic diathesis] combined with [specific environmental stressor]; neither factor alone typically causes onset."

Watch Out: Don't treat diathesis-stress as purely additive—it's interactive. Always include both components with specific examples.

SECTION B MARK SCHEME (6 marks) 0 marks: No relevant knowledge. 1–2 marks: Basic definition; minimal application. 3–4 marks: Both components described; partial application. 5–6 marks: Both components (diathesis = biological vulnerability; stress = environmental trigger) correctly defined with threshold concept; schizophrenia example uses empirically specific stressors (cannabis use, urban environment); interactionist framing explicitly contrasted with purely biological or environmental explanations.

Why Full Marks

Both components (diathesis = biological vulnerability; stress = environmental trigger) correctly defined with threshold concept; schizophrenia example uses empirically specific stressors (cannabis use, urban environment); interactionist framing explicitly contrasted with purely biological or environmental explanations.

Model Answer

High-Scoring Sample

Section A Sample Answer

The Diathesis-Stress Model posits that behavior and mental disorders result from an interaction between a biological vulnerability (diathesis) and environmental triggers (stress). An individual may carry a genetic predisposition for a condition, but it will only manifest if environmental stressors reach a specific threshold.

This is illustrated by the manifestation of Schizophrenia. An individual may have a high genetic risk (diathesis), but in a stable, low-stress environment, they may never show symptoms. However, if that same individual experiences significant environmental stress—such as chronic cannabis use during adolescence or living in a high-density urban environment—the "stress" activates the "diathesis." This demonstrates that schizophrenia manifests only when genetic vulnerability interacts with specific environmental triggers, supporting an interactionist explanation of behavior.

Section B Sample Answer

The diathesis-stress model posits that behavioral outcomes result from an interaction between a biological vulnerability (diathesis) and a stressful environmental trigger. In this scenario, a student might have a diathesis, specifically a genetic predisposition linked to the short allele of the 5-HTT gene, associated with heightened serotonin sensitivity and stress reactivity. While this vulnerability remains dormant in a traditional library, the high-tech, open innovation hub acts as the specific environmental stressor. This explicitly demonstrates the model because the interaction between the student's internal vulnerability and the external environment triggers the stress response that leads to the observed performance decrease.