part of 365 ISSN 1758-2008 10.2217/NPY.12.47 © 2012 Future Medicine Ltd Neuropsychiatry (2012) 2(5), 365–367 1 Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA 2 Department of Psychiatry, University of Florence, Via delle Gore 2H 50100, Florence, Italy 3 Institute of Neuroscience, viale Ugo Bassi 1, 50137, Florence, Italy *Author for correspondence: Tel.: +39 0555 87889; Fax: +39 0555 81051; stefanopallanti@yahoo.it Obsessive–compulsive disorder (OCD) is a complex and disabling disorder. The core of the complexity is the fact that OCD is a heterogeneous disorder with respect to its clinical presentation (i.e., age at onset, pharmacological response, pattern of comorbidities and symptom dimensions), and its neurobiological and neurocogni- tive dysfunctions. Among these complex clinical pictures, the manifestation of a condition with prevalent hoarding symp- toms has been proposed as a separate dis- order and its potential diagnostic criteria are now under revision for the inclusion in the DSM-5 [101] . There are two main issues: is there suffi- cient evidence to conceptualize hoarding as a separate disorder from OCD? And what would be the utility of separating hoarding disorder from OCD? The answer to the first question is the most complex. In fact, from a neuro- scientific perspective, the categorical dis- section of a brain disorder from another must take into account the systematic evaluation of several dimensions, ranging from genetics to clinical phenomenology. The epistemological input for an opera- tion of this kind is usually represented by epidemiological studies. In this case, the prevalence of hoarding in OCD samples seems to vary consistently across studies, but the overlap is significant. However, a recent meta-analysis demonstrates that this dimension may be regarded as an inde- pendent factor [1] , suggesting that the issue needs to be methodically examined and deserves better conceptualization in order to definitely view hoarding as a subtype of OCD or, rather, a discrete and sepa- rate disorder. If carefully analyzed, many differences can be found. First, some discrepancies in the phenomenological gestalt of the two con- ditions are worth highlighting. Obsessions are typically and tautologically defined as intrusive and egodystonic, whereas, often, thoughts related to hoarding and EDITORIAL “ ...the manifestation of a condition with prevalent hoarding symptoms has been proposed as a separate disorder and its potential diagnostic criteria are now under revision for the inclusion in the DSM-5. ” Is hoarding a diferent disorder? Stefano Pallanti* 1,2,3 Giacomo Grassi 2 Andrea Cantisani 2 “ ...the creation of a new diagnosis in the DSM-5 is desirable not just for hoarding, but also for other OCD dimensions, such as symmetry/ordering, and for other OCD subtypes. ”