Lumping versus splitting: A commentary on subtyping in OCD

This commentary discusses a number of pertinent concerns that were raised in this special series on subtyping in obsessive-compulsive disorders (OCD). The central question addressed in the three articles in the series is whether a better subtype classification of OCD could be developed if it is based on type of faulty cognition as well as symptom presentation. It is concluded that a more cognitive approach to OCD subtyping may not address many of the problems inherent in subtype research, nor will the development of special manualized treatment protocols for OCD subtypes necessarily yield significant improvements in treatment effectiveness. An alternative to OCD subtyping based on a categorical perspective is some form of profiling that recognizes the dimensional nature of OCD symptom and cognition variables.