Defining, operationalizing and measuring the duration of untreated psychosis: advances, limitations and future directions

Objective: Substantial converging evidence from schizophrenia researchers indicates that the duration of untreated psychosis (DUP) represents a modifiable predictor of outcome during the early course of schizophrenia. As DUP is increasingly assessed in research settings, focused attention should be given to the complexities of measurement of this critical construct. In this review, three aspects of measurement are addressed: (i) definition of DUP, (ii) operational criteria for the construct, and (iii) methods used for measurement. Recent advances, current limitations and future directions are discussed. Methods: Inclusion of published articles for this systematic review was based on two recent seminal meta-analyses examining associations between DUP and outcomes. Other relevant articles were reviewed to glean information on standardized instruments used to date and limitations regarding measurement of DUP. Results: Whereas the general definition of the DUP construct has been quite consistent across research groups, considerable variability exists in the operationalizations of the onset and endpoint of DUP. Several standardized instruments have been developed to measure DUP, although many articles fail to discuss reliability and validity of measurements. The literature lacks comparative assessments of the relative reliability and validity of the various measures and methods used to assess DUP. Conclusions: Given the importance of DUP and implications for secondary prevention, the complicated measurement issues that arise in quantifying this construct are addressed. A number of important advances from a variety of research groups have made the systematic assessment of DUP feasible and of great value for early psychosis research. Yet, several limitations must be considered as measurement of DUP progresses.