Overview of obsessive-compulsive disorder

INTRODUCTION

Obsessive-compulsive disorder (OCD) is one of the more disabling and potentially chronic anxiety disorders. It is characterized by anxiety-provoking intrusive thoughts and repetitive behaviors. Obsessions may consist of aggressive thoughts and impulses, fears of contamination by germs or dirt, or fears of harm befalling someone. Compulsions such as washing, checking, or counting are rituals whose purpose is to neutralize or reverse the fears. Related disorders include trichotillomania (hair-pulling) and Tourette syndrome.

EPIDEMIOLOGY AND SPECTRUM OF DISEASE

OCD occurs in 2 to 3 percent of the United States population [1]. There is probably a bimodal distribution of the age of onset, with studies of juvenile OCD finding a mean age at onset of around 10 years, and adult OCD studies finding a mean age at onset of 21 years [1-4]. Early onset OCD has been associated with a higher frequency of tic-like compulsions and comorbid tic disorders [5,6]. (See "Tourette syndrome".) In general, the modal age of onset is younger for males than for females [7]. There has traditionally been a significant delay between symptom onset and treatment seeking because of patient embarrassment and the long held perception (by both the patient and the medical community) that little can be done about the symptoms of OCD. OCD may occur at a higher during pregnancy and postpartum.

OCD shares many features with somatoform disorders, dissociative disorders, eating disorders, impulse control disorders, and neurologic disorders (table 1). These diseases have been classified under the rubric "obsessive-compulsive spectrum disorders" and are thought to approach a prevalence rate in the primary care setting of 10 percent [8]. An expert consensus guideline has determined that bulimia and body dysmorphic syndrome also are conditions in this spectrum that can be treated with similar pharmacologic agents as in OCD [9]. Hypochondriasis, trichotillomania, nail-biting, and skin-picking are conditions commonly seen in the medical setting that also are possibly responsive to OCD treatment.

In addition to significant disability and burden to patients and their families, total costs of OCD were estimated at $8 billion in 1990 [10]. More recent analyses estimate lifetime indirect costs due to lost wages at $40 billion [11].

PATHOPHYSIOLOGY

There is a higher incidence of OCD among first degree relatives of patients with OCD than in the general population. Orbitofrontal dysfunction [12] and frontal/parietal white matter changes [13] have been identified in patients with OCD, as well as their unaffected first degree relatives, suggesting a possible endophenotype for this disorder.