clear clinical utility, with a specific outcome activated by the score. For example, a PRS for coronary artery disease assessed in early adulthood may be useful to encourage healthy behaviour throughout life, although we still lack experience of how to use genetic data to motivate behaviour change [43–45]. Not all preventive strategies are so benign; pharmacological interventions or surgical procedures are more controversial. For example, it would be very difficult to consider prophylactic mastectomy for breast cancer prevention. Even simple decisions like increased screening may result in false positives with significant economic cost to society and unnecessary stress of the individual. At its simplest, PRS may be used to estimate an individual’s lifetime risk of disease. This application follows the design of most genome-wide association studies, differentiating between cases and controls. From the studies performed in different clinical areas assessing the predictive ability of PRS, we discuss below the strongest evidence for potential clinical utility, with special reference to our research area, psychiatric disorders [46].
