Stress, reactivity, and disease.

In summary, this work is an ambitious attempt to address some key issues in regard to the clinical importance of reactivity. The authors should be complimented for their efforts in addressing these issues, especially in small children. However, it is necessary to view their data in light of both the studies' strengths and weaknesses and to evaluate the implications of the work in light of existing theory and evidence. From this perspective, we think the work provokes interesting ways to think about reactivity. However, it leaves to subsequent research the task of systematically addressing the many issues that it raises.