N-of-1 trials are a type of research study designed to evaluate the effects of a treatment on a single individual. In these trials, the participant undergoes multiple treatment phases, alternating between the treatment and a control (like a placebo). This approach allows researchers to observe how the individual responds to the treatment over time, providing personalized insights. These trials are particularly useful in fields like medicine and psychology, where responses to treatments can vary widely among individuals. By focusing on one person, N-of-1 trials can help tailor interventions to meet specific needs, improving overall treatment effectiveness.