Purpose of review: Controversy exists about the diagnostic grouping of obsessive-compulsive spectrum disorders (OCSDs) - conditions that are to some extent related to obsessive-compulsive disorder (OCD). This review will re-examine OCSDs in light of the currently available evidence.
Recent findings: It appears that OCSDs will not constitute a separate nosological group and, if this term is accepted, OCSDs may be grouped together with the anxiety disorders. Much needs to be done to refine the criteria for membership in the OCSDs. In contrast to previous proposals, only a few disorders may be included in the spectrum. The most likely candidates for membership are body dysmorphic disorder and hoarding disorder, if the latter becomes an independent condition. Mixed, but relatively strong, support for inclusion also exists for Tourette's disorder and trichotillomania.
Summary: The concept of OCSDs is largely a product of an unbridled nosographical activity, resulting from a selective focus on the similar clinical features and an oversight of the important differences. While the links between some of the putative OCSDs seem important, the question remains as to whether the introduction of the spectrum to a diagnostic and classification system would significantly improve our understanding of these links.