Obsessive-Compulsive Disorder

Obsessive–Compulsive Disorder

Definition and Overview

Obsessive–compulsive disorder (OCD) is an intriguing and often debilitating syndrome characterized by the presence of two dis-tinct phenomena: obsessions and compulsions. Obsessions are intrusive, recurrent, unwanted ideas, thoughts, or impulses that are difficult to dismiss despite their disturbing nature. Compul-sions are repetitive behaviors, either observable or mental, that are intended to reduce the anxiety engendered by obsessions. Both obsessions and compulsions have been described in a wide variety of psychiatric and neurological disorders. However, ob-sessions and compulsions that clearly interfere with functioning and/or cause significant distress are the hallmark of OCD.

Although OCD was originally considered rare, findings from the Epidemiologic Catchment Area (ECA) survey in 1984 demonstrated that OCD was 50 to 100 times more common than had been previously believed. With increasing recognition of OCD, both in the mental health field and in the media, many indi-viduals with OCD have pursued treatment for this disorder. This has led to systematic investigation of clinical features such as symptom subtype, course, comorbidity, and the role of insight both descriptively and as mediators of treatment response.

These studies, conducted over the past 15 years, have greatly furthered our understanding of the clinical characteris-tics of this disorder. OCD is now considered a relatively common disorder that usually has its onset during puberty, although it may begin as early as age 2 years and infrequently begins after age 35 years. Women develop OCD slightly more often than men. Earlier studies found that the course of OCD is usually chronic, with symptom severity waxing and waning over time. However, those studies, which had a number of methodological limitations, were conducted prior to the availability of effective treatments for this disorder. More recent evidence suggests that some indi-viduals have a more episodic and favorable course.

Several large studies have found that the most common obsession is contamination, and the most common compulsion is checking. However, most individuals with this disorder have mul-tiple obsessions and compulsions over time. A number of psychiat-ric disorders cooccur with OCD, major depressive disorder being most frequent. Comorbidity with tic disorders is well established. That association plus a familial relationship between OCD and tic disorders has led to suggestions that tic-related OCD is a specific phenotype of OCD that is more closely related to tic disorders.

There has been considerable interest in the role of insight, or awareness, in OCD. An ability to recognize the senselessness of the obsessions and the ability to resist obsessional ideas have been considered fundamental components of OCD. However, research findings during the past decade have demonstrated a continuum of insight in this disorder, which ranges from excellent (i.e., complete awareness of the senselessness of the content of the obsessions), through poor insight, to delusional thinking (i.e., the obsessions are held with delusional conviction). To reflect these findings, the Diag-nostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) established a new OCD specifier – with poor insight – and also noted that, in cases of delusional OCD, an additional diagnosis of delusional disorder or psychotic disorder not otherwise specified may be appropriate (American Psychiatric Association, 1994).