similarity, course of illness, high comorbidit y, and shared treatmen t response. These indi-
cators served as empirical guidelines to info rm decision making by the work groups and
the task force about how to cluster disorders to maximize their validity and clinical utility. 
A series of papers was developed and published in a prominent international journal
(Psychological Medicine,  Vol. 39, 2009) as part of both the DSM-5 and the ICD-11 develop-
mental processes to document that such valid ators were most useful for suggesting large
groupings of disorders rather th an for “validating” individual disorder diagnostic criteria.
The regrouping of mental disorders in DSM-5 is intended to enable future research to en-