The psychosis threshold in Ultra High Risk (prodromal) research: is it valid?

"Transition to psychosis" has been the outcome of interest in Ultra High Risk (UHR) and "prodromal" studies. However, the point at which an individual crosses the line from high risk or prodromal state to psychosis threshold is arbitrary. There have been few attempts to examine whether this threshold has any validity in terms of biological markers or course and outcome. More research is needed to determine if the current point at which a person is declared "psychotic" is valid. Indeed some persons labeled as having developed psychosis may quickly recover. In such a situation their transition could be seen as "trivial". Others who do not make "transition" may have worse outcomes. Validation of the transition point is an important issue as "risk syndrome for psychosis" (psychosis prodrome) is being considered for inclusion in the DSMV. Further, much research attempts to distinguish markers for psychotic disorders by examining the differences between UHR individuals who do and do not develop psychosis. Thus it behooves us not just to have this risk syndrome validated, but to have the hypothetical endpoint of psychosis validated as well. (c) 2010 Elsevier B.V. All rights reserved.