Our knowledge of the prevalence and demographic and clinical characteristics of obsessive-compulsive disorder (OCD) has, until recently, been based almost exclusively on patient samples. The epidemiology of OCD was first described in a large United States household sample from the Epidemiologic Catchment Area (ECA) study. Since these original observations, the rates of OCD in household populations determined from diagnostic procedures similar to those used in the United States have been published from different parts of the world. Detailed comparisons of rates, sex ratios, age at onset, and demographic and clinical characteristics of OCD in these samples are now available.

This article reports on the cross-national epidemiology of OCD from seven international epidemiologic surveys, including the United States ECA study. Each survey used the Diagnostic Interview Schedule (DIS), a highly structured interview, developed for use in epidemiologic surveys, that yields Diagnostic and Statistical Manual of Mental Disorders, Third Edition (DSM-III) psychiatric diagnoses. All investigators provided the data from their study to be pooled at Columbia University, and the prevalence rates were standardized to the age and sex distribution of the five-site ECA household population so that more precise estimates and comparisons could be made.

This study investigates lifetime prevalence rates, demographic characteristics, childhood conduct disorder and adult antisocial features, suicide attempts, and cognitive impairment in individuals with obsessive-compulsive disorder (OCD) uncomplicated by or comorbid with any other psychiatric disorder. The data are from the NIMH Epidemiological Catchment Area (ECA) study, and the current analyses compared subjects with uncomplicated OCD (no history of any other lifetime psychiatric disorder) comorbid OCD (with any other lifetime disorder), other lifetime psychiatric disorders, and no lifetime psychiatric disorders across these variables. OCD in its uncomplicated and comorbid form had significantly higher rates of childhood conduct symptoms, adult antisocial personality disorder problems, and of suicide attempts than did no or other disorders. Comorbid OCD subjects had higher rates of mild cognitive impairment on the Mini-Mental Status Exam than did subjects with other disorders. These findings suggest that a subgroup of OCD patients may have impulsive features, including childhood conduct disorder symptoms and an increased rate of suicide attempts; wider clinical attention to these outcomes is needed.

Research in children and adolescents with obsessive-compulsive disorder (OCD) is increasing in both quantity and quality. This session will focus on new and exciting research findings regarding family genetic studies, infectious and immune etiologies, pediatric psychopharmacology, and cognitive behavioral treatment.

Neurobiological studies continue to generate new clues to the pathophysiology of obsessive-compulsive disorder (OCD). Currently, the weight of evidence implicates serotonin (5-hydroxytryptamine, 5-HT) receptor dysfunctions, but there is also evidence for abnormalities in other neurotransmitters, such as dopamine and noradrenaline, in neuropeptides, and for infective and immunological mechanisms. Such findings foster further questions, in particular the identification of the 5-HT receptor subtype involved, the meaning of the serotonergic abnormalities described thus far, and their relationships with the evidence of dysfunctions of other systems.

Certainly, new horizons can now be prospected for biological research in OCD with the ultimate goal of identifying the substrates of the clinical heterogeneity and of offering patients more targeted treatments.

An overview is provided regarding neuroimaging in obsessive-compulsive disorder (OCD). The author emphasizes convergent research results across various experimental paradigms and their implications for neurobiological models of OCD. The article concludes with an outline of future considerations that highlights emerging concepts and techniques. This work was intended to serve as a concise summary of the field, and thus to provide a springboard for discussion about this topic at the upcoming International Obsessive Compulsive Disorder Conference.

Transcranial magnetic stimulation (TMS), a relatively noninvasive probe of cortical function, permits new kinds of explorations of relationships between regional brain activity and symptomatology in obsessive-compulsive disorder (OCD). In TMS, a pulsed magnetic field affects activity in cerebral cortex underlying an electromagnetic coil placed on the scalp. Results of exploratory studies suggest that the single- or paired-pulse TMS techniques, and the newer repetitive method (rTMS), in which trains of stimuli are delivered at a given frequency, are potentially useful probes of cortical mechanisms involved in psychopathologic conditions, as in studies of motor, sensory, and cognitive physiology. For example, single-pulse TMS of motor cortex can produce muscle potentials or movement. Higher-frequency repetitive stimulation (rTMS) of occipital cortex can produce phosphenes or visual extinction, stimulation of Broca's area results in word-finding difficulties or speech arrest, and rTMS of prefrontal cortex affects verbal recall and other cognitive functions. Prefrontal rTMS can alter mood in healthy individuals. Both open and controlled clinical studies suggest that single-pulse TMS, and rTMS, may have antidepressant effects. Although the cerebral cortex is the only human brain structure subject to direct magnetic stimulation with current technology, TMS may influence activity in subcortical sites via their functional relationships with cortical areas. The effects of TMS on cortical excitability may depend on a combination of factors including coil design, stimulus frequency and intensity, and possibly the functional state of the cortex before stimulation.

Obsessive-compulsive disorder (OCD) was thought to be a rather rare disorder and little attention was focused on investigations of the disorder until the first placebo-controlled studies reported efficacy. In 1980 three pivotal papers were published: Montgomery reported that clomipramine was effective in OCD without concomitant depression, and Thoren et al and Marks et al reported that clomipramine was effective in OCD with varying amounts of concomitant depression. These results opened the floodgates of psychopharmacological research and encouraged a more aggressive research program aimed at providing sufficient data for OCD to be recognized as a treatable condition.

The comorbidity of schizophrenia and obsessive-compulsive disorder (OCD) might be approached from two different directions. One is the OCD with psychotic features, and the other is the schizophrenic patient with OCD.

The lumping together of the seven deadly sins—pride, covetousness, jealousy, sloth, lust, gluttony, and anger—is, of course, a theological categorization rather than a medical nosology. Nevertheless, these seven sins are oddly reminiscent of various symptoms of a common medical disorder—one that has received increasing neuroscientific investigation in recent years—obsessive-compulsive disorder (OCD). Is such a parallel between sin and symptom purely coincidental, or is modern neurobiology able to provide a more coherent explanation?

Interestingly, the term “obsession” derives from the Roman Catholic concept of obsession—a state of being possessed by the devil. Indeed, obsessions—defined as recurrent intrusive and senseless thoughts and images—are some of the most overwhelming and distressing of psychiatric symptoms. While it is true that hallucinations and delusions lead to a loss of contact with reality, people with obsessions suffer from the very fact that they cannot resist ideas that they know full well to be irrational. Thus, OCD sufferers find themselves having to perform compulsions—recurrent rituals that relieve anxiety—but which are not realistically connected to the preceding obsessions or are clearly excessive.

The study presented was conducted to analyze the effects of obsessive-compulsive symptoms on patients' quality of life and the costs incurred by patients and society for the treatment of obsessive-compulsive disorder (OCD). To accomplish this, a detailed 410-item questionnaire of psychosocial function and economic cost was sent to every fourth member of the Obsessive Compulsive Foundation. Of the 2,670 members who received the survey, 701 (26.9%) returned it.

Outcome measures included symptomatology, course of illness, impact of illness on psychosocial and other functioning, effects of diagnosis and treatment, and economic consequences. The demographics of this group were similar to those in smaller treatment-seeking clinical samples, but not necessarily to OCD sufferers within the US population as a whole. More than half of the patients reported moderate to severe interference in family relationships, socializing, and ability to study or work, secondary to OCD symptoms. A 10.2-year gap was observed between the onset of symptoms and the first attempt to seek professional help, and a 17.2-year gap was observed between the onset of symptoms and receipt of effective treatment. Specific treatments, such as serotonin reuptake inhibitors and behavior therapy, showed greater symptom improvement, and significantly reduced the total annual fees incurred by OCD patients when compared with nonspecific treatments.

Our study results indicate that OCD has a profound effect on psychosocial functioning and quality of life. Large direct costs for OCD and even larger indirect costs due to lost wages and underemployment were found. Greater awareness of OCD among practitioners may result in earlier diagnosis and more appropriate and cost-effective treatments.