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IB DP Psychology — Health Psychology (Contexts) | SL & HL | Paper 2
🎯 Learning Intentions By the end of this note, you will be able to:
- Define health promotion, adherence, and the biopsychosocial model using IB-aligned terminology.
- Explain how psychological factors — including beliefs, motivation, and social support — influence whether individuals adopt preventive health behaviours.
- Describe the Health Belief Model (HBM) and its core components, including perceived susceptibility, severity, benefits, barriers, and cues to action.
- Evaluate research evidence for health promotion and treatment adherence using supporting and opposing studies in ACAS format.
- Explain why patients fail to adhere to medical treatment and the psychological strategies used to improve adherence.
- Apply concepts of prevention and treatment to a real-world case study from biological, cognitive, and sociocultural perspectives.
- Discuss the extent to which psychological interventions can effectively prevent illness and improve treatment outcomes.
- Analyse prevention and treatment research using relevant concept areas: Bias, Causality, Change, Perspective, and Responsibility.
Introduction & Context
Imagine two people who both receive the same advice from their doctor: exercise more, eat better, and take a daily medication to manage their blood pressure. Six months later, one person has transformed their lifestyle and takes their medication without fail. The other has barely changed anything. Both received identical information — so why did they respond so differently? The answer lies not in the information itself, but in how each person thought about it, felt about it, and what their social environment reinforced.
Health psychology is the branch of psychology concerned with understanding how psychological, behavioural, and social factors influence physical health. Within this field, two of the most practically important questions are: how do we stop people from becoming ill in the first place (prevention), and how do we help people who are already ill to follow through with the treatments they need (adherence)? These are not simply medical questions — they are deeply psychological ones, shaped by beliefs, emotions, identity, and social context.
The traditional biomedical model of health focused almost exclusively on biological causes and cures. However, decades of research have demonstrated that this model is incomplete. People do not make health decisions based purely on objective risk — they make them based on how they perceive risk, what they believe about their own vulnerability, and whether they feel capable of change. Understanding these psychological processes is essential for designing effective health interventions.
🔍 Analogy — The Smoke Alarm and the Locked Door Think of health prevention like a smoke alarm in a building. The alarm (health information) can go off loudly, but whether people actually evacuate depends on whether they believe the fire is real, whether they think they can get out safely, and whether others around them are moving toward the exit. Simply having the alarm is not enough — the psychological response to it determines behaviour. Treatment adherence works similarly: knowing you need to take medication is the alarm, but actually taking it consistently depends on beliefs, habits, and support systems.
Core Concepts
Before we can understand how to prevent illness or improve treatment, we need a framework for thinking about health itself. For most of the twentieth century, health was defined almost entirely in biological terms — disease was caused by pathogens, genetic defects, or physiological dysfunction, and treatment meant correcting those biological problems. This view, while useful, left out a vast amount of what actually determines whether people get sick, stay sick, or recover.
📖 Key Definition — The Biopsychosocial Model The biopsychosocial model (Engel, 1977) proposes that health and illness are determined by an interaction of biological factors