Mental health articles

obsessive compulsive disorder (OCD) Epidemiology
The now well-known Epidemiological Catchment Area (ECA) survey conducted during the early 1980s indicated lifetime prevalence rates for OCD of 1.9 to 3.3% in five U.S. communities and an overall rate of 2.5%. These rates were much higher than any previous estimates and were conf irmed by similar epidemiological, albeit smaller scale, surveys conducted at approximately the same time in the United States and Canada. In all of these studies, however, interviews were conducted by lay interviewers, and it is notable that prevalence estimates were considerably lower in surveys using clinician interviewers.
In fact, a more recent study confirmed that prevalence rates for OCD within a single sample were indeed lower when clinicians, rather than lay interviewers, conducted diagnostic interviews. Issues such as lay interviewers’ inexperience in establishing and labeling psychiatric symptoms and difficulty in estimating degree of dysfunction and distress are particularly relevant in this regard. The limitations of the ECA study are well known and have been discussed in detail elsewhere. The most striking of these, however, are the aforementioned potential for overdiagnosis due to use of lay interviewers and diagnostic structured interview tools that do not allow for follow-up questions to clarify patient reports. Of even more concern are recent data suggesting poor temporal stability of OCD diagnoses for a subset of ECA survey participants who were reassessed 12 months after the initial interview. Taken together, these data call into question prevalence rates based on the ECA survey. It is unfortunate that the only subsequent large epidemiological survey conducted in the United States, the National Comorbidity Survey, failed to assess the prevalence of OCD. As a result, the true prevalence of this disorder is now uncertain. At least partly due to general difficulties in estimating prevalence rates, data are mixed with regard to the impact of ethnicity on the prevalence of OCD.
Across all five ECA sites, figures indicated that lifetime OCD was significantly less prevalent among Black respondents than nonHispanic White respondents. Data from the Los Angeles site alone indicated no difference in prevalence rates for OCD among Mexican-Americans and non-Hispanic Whites. When ECA data were compared with surveys that used similar methodology in Canada, Puerto Rico, Germany, Taiwan, Korea, Hong Kong, and New Zealand, relatively consistent prevalence figures emerged (1.9–2.5%), except Taiwan where the prevalence of OCD was only 0.7%. In a more recent survey of more than 800 residents of Baltimore, OCD tended to be more prevalent among Whites (2.1%) than non-Whites (0.8%). Clinical data also routinely show a greater prevalence of OCD among Whites than non-Whites. It is not clear, however, that interview questions are always sensitive to ethnic differences in the experience or description of relevant symptoms. It is known, for example, that members of various minority groups tend to focus on somatic complaints in descriptions of anxiety-related symptoms and often present for assistance to medical rather than psychiatric clinics.
Other sociocultural variables, including religious background, can also significantly impact the presentation and assessment of OCD symptoms. Thus, more research using culturally sensitive diagnostic tools is needed to ascertain the impact of ethnicity on prevalence rates of OCD. Epidemiological data generally have indicated that community prevalence rates are slightly higher for women than men. However, data from the ECA survey indicated that gender effects were eliminated when other demographic variables were controlled statistically. Nevertheless, consistent gender differences have been demonstrated in the prevalence of specific obsessive-compulsive symptoms. In particular, women are significantly more likely than men to report washing and cleaning rituals, and there is some suggestion that men report more frequent sexual obsessions. These findings further support the potential role of sociocultural variables in the presentation of OCD. Gender differences have also been noted in the onset of OCD.
lthough the disorder most often begins between late adolescence and early adulthood, onset is earlier for males than females. Retrospective data have suggested that later onset for women may result from the appearance of initial symptoms during pregnancy or after childbirth. However, these f indings simply may reflect the notion that OCD often has its onset after a period of significant life stress, although data addressing this issue are almost uniformly collected retrospectively and produce questionable conclusions. Although few longitudinal studies have been conducted, the course of OCD is generally chronic and unremitting without treatment.

Tags: disorder, epidemiology, obsessive compulsive disorder, OCD