135 Discussion: what might be common elements that could contribute to OCD spectrum disorders? The relationships among OCD comorbid disorders and additional OCD spectrum disorders: old and new postulated groupings From an overview perspective, OCD remains as a distinct clinical entity, with classic

symptoms and behaviors involving obsessions and compulsions plus high anxiety and, over the lifetime, the occurrence of mood and other anxiety disorders. OCD differs from the other anxiety disorders by its earlier age of onset, more complex comorbidity, and severity of obsessional thoughts and compulsive behaviors. OCD as defined Inhibitors,research,lifescience,medical in DSM-IV/IV-TR also occurs concomitantly with other DSM-defined disorders ranging from body dysmorphic disorder, Tourette AG-014699 in vitro syndrome, eating disorders, and autism spectrum disorders,118 as well as multiple other disorders. Individuals with these other primary disorders Inhibitors,research,lifescience,medical may have separately defined OCD meeting full criteria. There seem to be two views about this overlap: (i) All of these disorders together constitute an OCD

spectrum group, with implications that they are all manifestations of a single OC-based entity; or (ii) each may be an independent coexisting disorder. For some individual patients, it may be that a mixture of both may be operative for Inhibitors,research,lifescience,medical different components of these disorders. Thus, the relationship among OCD-related disorders remains uncertain. Inhibitors,research,lifescience,medical We have noted that a number of other disorders have sometimes been named in an extended list of OCD spectrum disorders (Figure 2) such as the impulsive disorders; however we will not discuss them further, as their association to OCD is tenuous and not acknowledged by most experienced

clinicians and researchers or recent reviews.19 On the other hand, we have explicitly added two additional groupings of OCD-related disorders that Inhibitors,research,lifescience,medical are not based on descriptive nosology, but rather on etiologic considerations ( Figure 3). One of these links acute OCD onset to environmental events such as the consequences of infection, traumatic brain injury, and other neurological disease insults. The other newly suggested OCD spectrum encompasses etiologies related to specific gene or narrow chromosome region-related syndromes – a fourth genomic OCD-related group. Some of this latter group also overlaps with second disorders such as Tourette syndrome, with its common tripartite combination of tic disorders, OCD, and ADHD. It is of interest that some considerations for DSM-5 and future DSMs are beginning to show additional elements beyond clinical symptoms as bases for designation of an entity. These include biological, psychophysiological, and brain imaging data as well as potential etiological factors including genetic elements and brain neurocircuitry contributions.6,12,14,19,22,25-26 Figure 3.