From a public health perspective, there must be more than just concurrent correlations between a trait and adverse outcomes. The public health significance of any trait depends heavily on its ability to predict future adverse outcomes with an effect size large enough to be of practical importance. In the absence of such predictive utility, neuroticism could not usefully identify individuals at high risk for future adverse outcomes. Furthermore, if neuroticism did not predict future outcomes and demonstrate temporal precedence relative to the outcomes, it would be unlikely that neuroticism could be causally related to those outcomes. It is very important, then, that a number of prospective longitudinal studies have indicated that neuroticism has substantial predictive utility for a number of mental health outcomes.
