Figure 2 provides a depiction of the original and modified groupings of OCSD and OCRD disorders, including notation of other disorders considered by some as part of a compulsive-impulsive spectrum group of disorders. Some re-evaluations of these relationships have been published recently, 12,19,21,27,61,73-75 and reflect the ongoing debate about genetic and environmentallyshaped, neurodevelopmental elements related to OCD

onset that also may impact the future status of OCD in DSM-5. Figure 2. OCD and disorders comorbid with OCD Table II indicates the frequency of comorbid disorders found in adult probands with OCD compared with the incidence of these disorders in the general US population. Inhibitors,research,lifescience,medical As is evident, two- to sixfold higher prevalence rates of most psychiatric disorders are found in individuals with OCD. Most striking are the high frequencies of all anxiety disorders taken together, and likewise, all affective disorders. Also of interest are the lack of differences in alcohol-related and substance Inhibitors,research,lifescience,medical abuse disorders between those with OCD and

the general US population. Specific symptomatologic features that potentially may be useful for grouping OCD into more homogeneous and familial phenotypes for etiologic investigations include those of comorbid tic, affective, Inhibitors,research,lifescience,medical anxiety and the other disorders listed, as well as obsessive-compulsive personality disorder. An example of one OCD-comorbid disorder (not listed in Table I Ibut recently identified as a potential OCRD disorder) is

attention-deficit hyperactivity disorder (ADHD).80,81 While some of the original OCD comorbid spectrum disorders remain in this grouping simply on Inhibitors,research,lifescience,medical the basis of consistent co-occurrence with OCD in descriptive samplings or overlapping features, others such as ADHD have been validated via segregation analysis. In evaluations of the OCD-ADHD Inhibitors,research,lifescience,medical relationship, relatives of probands with both disorders have been found to have a significantly higher frequency of OCD plus ADHD compared with the relatives of probands with ADHD found only80,81 Table II Disorders occurring together with OCD in five clinical investigations57,60,71,77,79 and one epidemiologic72 investigation of adult OCD (modified from refs 60,71,77 compared with the incidence of these disorders in the general … Apparent environmental etiology-based OCD-related disorders Three examples of full-blown OCD occurring apparently acutely de novo following putative causal events include: (i) OCD related to an infection such as that associated with PI3K inhibitor streptococcal infections (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections [PANDAS] syndrome); (ii) trauma-related OCD following acute brain injuries; and (iii) OCD occurrence during treatment of schizophrenia with atypical neuroleptic agents.