ABSTRACT
Since the earliest descriptions of obsessive-compulsive disorder (OCD) in the Western world, clinicians have recognized the heterogeneous nature of the syndrome. For example, as early as 1866, Falret (Falret, 1866) made the distinction between folie du doute (madness of doubt) and délire du toucher (delusion of touching; Hantouche & Lancrenon, 1996; Mataix-Cols, Rosario-Campos, & Leckman, 2005). Since then, several attempts have been made to classify persons with OC symptoms into homogeneous, usually mutually exclusive, subgroups (Mataix-Cols et al., 2005). These classificatory attempts have had various levels of success in terms of being related to patterns of neurobiological variables, genetic transmission, and treatment response. Despite this heterogeneity, the current classification systems-the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR)—still regard OCD as a single entity (American Psychological Association, 2000).
