Obsessive-compulsive disorder

Summary

Obsessive-compulsive disorder is a severe and disabling clinical condition that usually arises in late adolescence or early adulthood and, if left untreated, has a chronic course. Whether this disorder should be classified as an anxiety disorder or in a group of putative obsessive-compulsive-related disorders is still a matter of debate. Biological models of obsessive-compulsive disorder propose anomalies in the serotonin pathway and dysfunctional circuits in the orbito-striatal area and dorsolateral prefrontal cortex. Support for these models is mixed and they do not account for the symptomatic heterogeneity of the disorder. The cognitive-behavioural model of obsessive-compulsive disorder, which has some empirical support but does not fully explain the disorder, emphasises the importance of dysfunctional beliefs in individuals affected. Both biological and cognitive models have led to empirical treatments for the disorder—ie, serotonin-reuptake inhibitors and various forms of cognitive-behavioural therapy. New developments in the treatment of obsessive-compulsive disorder involve medications that work in conjuction with cognitive-behavioural therapy, the most promising of which is D-cycloserine.

Introduction

Obsessive-compulsive disorder is characterised by the occurrence of either obsessions, compulsive rituals or, most commonly, both.¹ Obsessions have four essential features: they are recurrent and persistent thoughts, impulses, or images that are experienced as intrusive and cause great anxiety; they are not simply excessive worries about real life issues; the affected individual attempts to ignore, suppress, or neutralise them with some other thought or action; and the affected individual recognises that these thoughts are a product of his or her mind.¹ Examples of obsessions include unwanted thoughts or images of harming loved ones, persistent doubts that one has not locked doors or switched off electrical appliances, intrusive thoughts of being contaminated, and morally or sexually repugnant thoughts (eg, intrusive thoughts of behaving in a way that violates one's morals or runs counter to one's sexual preferences).

Compulsions are repetitive behaviours (eg, repetitive hand washing, ordering, or checking) or mental acts (eg, repetitive praying, counting, or thinking good thoughts to undo or replace bad thoughts) that the affected individual feels compelled to do in response to an obsession, or according to rigid rules (eg, checking that a light switch is turned off by switching it on and off exactly ten times). Compulsions are aimed at preventing or reducing distress, or preventing some dreaded event.¹ However, they are excessive or not realistically connected to what they are intended to prevent.

Obsessive-compulsive disorder is a symptomatically heterogeneous condition, in which various different kinds of obsessions and compulsions exist. However, research indicates that certain obsessions and compulsions tend to co-occur to form five main dimensions:²

• obsessions about being responsible for causing or failing to prevent harm; checking compulsions and reassurance-seeking;

• symmetry obsessions, and ordering and counting rituals;

• contamination obsessions, and washing and cleaning rituals;

• repugnant obsessions concerning sex, violence, and religion;

• hoarding, which are obsessions about acquiring and retaining objects, and associated collecting compulsions.

Recent findings have supported these five dimensions across ages from childhood through adulthood.3, 4 Although hoarding has traditionally been regarded as a form of obsessive-compulsive disorder, the differences between hoarding and the other obsessive-compulsive symptom dimensions are compelling enough that some researchers now think that hoarding is a separate disorder.⁵

No laboratory tests exist for obsessive-compulsive disorder, and the diagnosis is made by clinical interview. To diagnose the disorder according to the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) criteria,¹ the affected individual must suffer from either obsessions or compulsions that cause great distress, are time-consuming (more than 1 h per day), or substantially interfere with normal functioning. At some point in the course of the disorder, the affected individual must also recognise that the obsessions and compulsions are excessive or unreasonable. This criterion does not apply to children because they may not have sufficient cognitive awareness to make this judgment. Also, commonplace childhood rituals (eg, avoiding cracks on the pavement) are not compulsions, they are not distressing or debilitating, and they tend to be transient.

Obsessive-compulsive disorder would not be diagnosed if obsessions and compulsions arose in the context of some other disorder such as schizophrenia. In such cases, the current diagnostic conventions (ie, International Classification of Diseases [ICD] and DSM) indicate that obsessive-compulsive symptoms are due to some other disorder (ie, schizophrenia). Here, we focus on obsessive-compulsive symptoms as they occur in what is currently called obsessive-compulsive disorder.

People with this disorder have varied insights into the senselessness of their symptoms,¹ with most acknowledging that obsessions and compulsions are at least somewhat unrealistic and excessive. Insight can be assessed by asking the patient how strongly he or she believes that the obsessions are realistic and that the rituals actually serve to prevent disastrous consequences.