Much of the activity is ineffective 4 and some may even make things worse. For conditions with multiple risk factors, such as coronary heart disease and also suicide, each factor adds a little to the risk, but often only when it interacts with other factors. No single predictor or combination of predictors is present in every individual, and membership of the high-risk group changes from moment to moment. Half a bottle of whisky may create a high suicide risk within an hour.
Many more suicides come from the very much larger low-risk population.
Another problem appears once we identify high-risk individuals. They then need advice and treatment that is effective, available and acceptable to them. If we look at population suicide rates, agencies such as telephone suicide crisis services seem ineffective. Those deemed at high risk, such as those discharged from hospital after a suicide attempt, already receive intensive follow-up, and further improvements will show diminishing returns of people saved. However, the insuperable problem in the high-risk approach arises when we try to use common characteristics of history and personality to identify individuals at risk of events that are uncommon in statistical terms.