Mental health articles

Types of OCD Disorders
Comorbidity, Differential Diagnosis, and the Obsessive-Compulsive Spectrum Disorders
OCD is frequently accompanied by increased levels of anxiety and depression; estimates of coexistent disorders range from 42–83% . Despite these high rates of overlap with other disorders, the diagnosis of OCD can be made quite reliably, particularly when behavioral compulsions are present. Key differential diagnostic issues still are relevant, however, and these will be reviewed briefly here.
Generally, the differentiation of OCD from other anxiety disorders is fairly straightforward. First, although there is clearly overlap between obsessional thinking and worry, as already noted, the diagnostic differentiation of OCD and GAD can be made reliably. In differentiating these disorders, it is of note that obsessions generally are associated with a greater degree of resistance and increased perceptions of unacceptability than worry.
Obsessions are also less likely to be precipitated by and focused on circumstances of daily living. Even when GAD is diagnosed in patients with principal OCD, it is associated with more frequent worries about daily life events.
Moreover, although repetitive checking may be present in GAD, rituals that accompany OCD are usually more pervasive and intrusive. Differentiation of OCD and other disorders with more focal fears (e.g., specific phobia, social phobia, specific subtype) is usually not difficult because any obsessional ideation that accompanies these syndromes revolves around a single fear. Ritualistic behavior also typically does not accompany fears with a more specific focus. The distinction between OCD and specific phobias of illness, however, can be slightly more complicated because fears of contamination/illness are the most prevalent form of obsessions generally reported. In these cases, differentiation can be relatively straightforward if rituals accompany the fear. In addition, specific phobias of illness involve more focused health-related fears than the pervasive concerns usually evident in OCD. Differentiating OCD and depression is also an important issue, given the high rates of comorbidity between these conditions. Although figures vary across studies, as many as one-third of patients with OCD also meet criteria for coexistent depression or dysthymia In these cases, it can be important for treatment planning to identify which disorder is considered principal. Generally, the principal disorder is assumed to be that with the earlier onset. Using this criterion, OCD more often is considered the principal diagnosis when both disorders are present. There is support, however, for the notion that all anxiety and affective disorders share a similar biological pathophysiology, although environmental factors shape symptom expression. Of more recent interest in the literature, however, are issues concerning the relationship between OCD and a wide range of other psychiatric and neuropsychiatric disorders that, it is hypothesized, comprise a group of disorders known as the obsessive-compulsive spectrum disorders. Disorders proposed as members of this spectrum include the somatoform disorders (e.g., body dysmorphic disorder, hypochondriasis), eating disorders (e.g., anorexia nervosa, bulimia nervosa, and binge-eating disorder), impulse control disorders (e.g., trichotillomania, pathological gambling) and related symptoms (skin picking, nail biting, and compulsive buying), and movement disorders (e.g., Tourette’s disorder, Sydenham’s chorea). These disorders, it has been hypothesized, share common phenomenological features, patterns of comorbidity, family history, clinical course, treatment response, and neurobiological mechanism with OCD. The proposed concept of obsessive-compulsive spectrum disorders has generated much controversy in the field. In particular, some authors have argued that this classification scheme is vague, overinclusive, and characterized by a lack of clear inclusion and exclusion criteria. Other authors have argued that the spectrum disorders are part of an even broader class of affective disorders. Subclassification schemes have also been proposed, and some include disorders of altered risk assessment, incompleteness/habit spectrum disorders, and psychotic spectrum disorders. Another perspective suggests that disorders along the obsessive-compulsive spectrum vary across a continuum of compulsivity versus impulsivity. In this scheme, compulsive disorders, it is proposed, reflect excessive harm avoidance and risk aversion, whereas impulsive disorders are characterized by minimization of harm and risk. Empirical literature addressing the potential overlap between OCD and the other proposed spectrum disorders is limited at present. Nevertheless, in some cases, the apparent overlap is more striking than in others. It has been suggested that those disorders that would be classified along the compulsive end of the spectrum (e.g., the somatoform and eating disorders) are more similar to OCD than those proposed that fall along the impulsive end (e.g., impulse control disorders). The extant literature supports this notion, at least in part because of striking phenomenological similarities between OCD and body dysmorphic disorder (BDD), hypochondriasis, and eating disorders. In particular, preoccupations with perceived physical defects, serious disease, and food or body weight that are present in BDD, hypochondriasis, and eating disorders, respectively, strongly resemble the obsessions that occur in OCD.
In addition, ritualistic behavior generally accompanies these other syndromes. For example, patients with BDD frequently check their appearance in the mirror, seek reassurance about the imagined physical defect, and perform excessive grooming behaviors. Patients with hypochondriasis often repetitively check physical symptoms, request medical treatment, and seek reassurance regarding health. Individuals with eating disorders also regularly report repetitive behaviors surrounding eating behaviors. In addition to these striking phenomenological similarities, there is some evidence that these disorders respond to pharmacological interventions (e.g., serotonergic reuptake inhibitors) and behavioral treatments (exposure and response prevention) that are the treatments of choice for OCD. Despite these areas of overlap between OCD and those spectrum disorders proposed, potentially important differences in these conditions are also evident. For example, both BDD and hypochondriasis generally are associated with greater levels of impaired insight than is typically seen in OCD. Additionally, bulimia nervosa and binge eating disorder are associated with more frequent impulsive behaviors than OCD.
Finally, there is some evidence that hypochondrias and eating disorders also respond to nonserotonergic antidepressants that have not demonstrated efficacy in OCD.
Nevertheless, the possibility that these disorders are related in some way to OCD deserves additional empirical attention. In the case of those disorders proposed that lie along the impulsive end of the spectrum, it is our opinion that differences among these disorders in phenomenology, neurobiology, and treatment far outweigh any similarities. The impulse control disorders (ICDs; e.g., pathological gambling, kleptomania, trichotillomania) and possible ICDs (e.g., nail biting, repetitive self-mutilation, skin picking) are characterized by repetitive behaviors over which patients report no control. These behaviors often, it is reported, have an anxietyrelieving function, and it is in these domains that there is some overlap with OCD. Other data also have suggested overlap between the ICDs and OCD in family history and treatment response.
Despite these areas of overlap, other phenomenological, neurobiological, and treatment data suggest important differences between OCD and ICDs. The majority of literature in this area has addressed the potential overlap between OCD and trichotillomania (TM), a disorder characterized by repetitive hair pulling. In a review of this literature, Stanley and Cohen summarized areas of similarity and dissimilarity between these conditions. One major phenomenological difference included the fact that obsessional thoughts usually do not accompany repetitive hair pulling, although this type of cognitive activity is central to the diagnosis of OCD.
In addition, hair pulling occurs in response not just to anxiety, but also to a variety of affective states, and the behavior frequently produces feelings of pleasure that are not characteristic of OCD. Moreover, sensory stimuli (e.g., itching, burning) are important precipitators of hair pulling, although these have no central role in OCD. Neurobiological and neuropsychological correlates of OCD and TM are also different, although the literature addressing these issues in TM is still somewhat limited. Finally, pharmacological treatment data for TM do not provide a consistent picture of the efficacy of serotonergic reuptake inhibitors, and the modes of behavioral treatment for TM (habit reversal training) and OCD (exposure and response prevention) are quite different. In summary, the range of important differences between these two syndromes calls into question the utility of combining them under a single spectrum of obsessive-compulsiverelated disorders.
However, Stanley and Cohen highlighted the notion that some subtypes of TM may reflect more overlap with OCD and further suggested that any appearance of association between these disorders may result from the heightened states of negative affect that accompany each. These hypotheses require further study. Overall, the notion of an obsessive-compulsive spectrum of disorders continues to generate controversy in the field. Difficulties in assessing the utility of this scheme reflect in part the fact that there are not yet any established criteria for membership in this family of disorders. Furthermore, the amount of literature that has provided direct comparisons between patients with OCD and those with proposed related disorders remains limited.

Tags: disorders, OCD