N-of-1 behavioural medicine: Revolutionizing health promotion in public health through personalized intervention

Behavioural medicine, at the intersection of behavioural science and medicine, aims to understand how behaviour influences health and to design interventions for better quality of life. Focusing on the interplay between behaviours, psychological processes, and biological factors, the field applies behavioural principles to prevent, diagnose, and treat medical conditions. Its key components include application of psychosocial and behavioural paradigms for the analysis of health promotion, disease prevention, and adherence to medical treatment. In public health, behavioural medicine plays a pivotal role by contributing to initiatives promoting healthy behaviours, identifying risk factors, and addressing social determinants of health. Despite its potential to contribute to this field, behavioural medicine has limitations, including the complexity of human behaviour and challenges in sustaining long-term behaviour change. In modern era medicine, focus is on evidence-based practice. In this context, N-of-1 trials, or single-subject trials, introduce a personalized approach to behavioural medicine research. The logic for the focus on individual patients is that 'each person is unique'. These trials focus on individual patients, systematically implementing and evaluating behavioural interventions over multiple cycles. By randomizing and blinding interventions, collecting repeated measures of outcomes, and prioritizing patient-centred outcomes, N-of-1 trials offer a nuanced understanding of how specific interventions impact individual health. While literature on N-of-1 trials in behavioural medicine is limited, they hold promise in tailoring interventions to individuals, addressing the diverse and dynamic nature of human behaviour in health contexts.