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Obsessive-Compulsive Disorder Not Just a North American Phenomenon
Pauline Anderson

February 14, 2008 ? Results of a new study show that obsessive-compulsive disorder (OCD) symptoms in Japanese patients are remarkably similar to those found in Western countries, suggesting that this disorder transcends culture and geography.

The study, published in the February issue of the American Journal of Psychiatry, appears to contradict previous theories, said the study?s lead author, Hisato Matsunaga, MD, PhD, from the department of neuropsychiatry at Osaka City University Medical School, in Japan. Dr. Matsunaga told Medscape Psychiatry that he was surprised by the study results. ?I hypothesized that symptom structure might be substantially influenced by the sociocultural differences.?

Instead, the study, the first comprehensive analysis of OCD symptoms in an Asian population, found that OCD is less a cultural and more a neurobiological phenomenon. The study found that, as in Western patients, 4 main symptoms account for the majority of variance in OCD outcomes among Japanese patients: contamination/washing; hoarding; symmetry/repeating and ordering; and aggressive/checking.

A Unique Culture

With its history of isolation, the Japanese are one of the largest populations with a single ethnicity, making it a unique culture to observe OCD, the authors write. And this cultural backdrop provides a useful context for comparison with research in the West.

The Japanese researchers analyzed 343 outpatients with a history of OCD for at least 2 years, many of whom had comorbid major depression. During pretreatment assessment, their functioning was assessed using the Global Assessment of Functioning. The mean GAF score was 49.6.

Ratings of OCD symptoms were obtained using the Japanese version of the Yale-Brown Obsessive-Compulsive Scale. The mean total score for the Yale-Brown and for obsession and compulsion subscale scores were 26.9, 13.7, and 13.2, respectively.

After this assessment, each subject was treated with a combination of a serotonin-reuptake inhibitor (SSRI) and cognitive behavior therapy (CBT). Atypical antipsychotics were added if the subject was nonresponsive to at least 2 trials of SSRIs combined with CBT.

After 1 year, the mean decrease in the Yale-Brown Obsessive-Compulsive Scale total score for the 295 subjects still in the study was 20.7%. All but 5% of the subjects (who had pure obsessions) presented a mixture of obsessions and compulsions. Contamination, at 48%, was the most common obsessive symptom, followed by symmetry or exactness (42%), miscellaneous (38%), and aggressive obsessions (36%). Rates of hoarding, somatic, sexual, and religious obsession were 12%, 12%, 10%, and 8%, respectively.

As for compulsive symptoms, checking and washing were the most common (at 47%), followed by repeated rituals and miscellaneous compulsions (31% each), ordering (22%), counting (14%), and hoarding compulsions (12%).

Further analysis found that 4 factors explained 57.7% of the variance:

Contamination/washing (accounting for 21.2% of the variance).
Hoarding (accounting for 14.3% of the variance).
Symmetry/repeating and ordering (accounting for 11.9% of variance).
Aggressive/checking (accounting for 10.3% of variance).
Similar Symptom Structure

These results reflect similar symptom structure as in the West, according to the authors. They suggest that ?transcultural stability in the symptom structure of OCD and the involvement of universal psychobiological mechanisms in the pathogenesis of the disorder.?

The study uncovered significant associations between major symptom categories. The most robust correlations were between: contamination obsessions and cleaning compulsions; aggressive obsessions and checking compulsions; ordering obsessions and compulsions; and symmetry obsessions and both repeating rituals and ordering compulsions.

Researchers also found some interesting ? and potentially clinically useful ? information about symmetry and hoarding obsessions. Symmetry was associated with an earlier age of onset and severity of OCD. Both symmetry and hoarding were significantly associated with decreased functioning and poorer treatment outcome.

These findings may help illuminate the underlying mechanisms of OCD, wrote the authors. ?There is growing evidence that early-onset OCD is a unique subtype of OCD, characterized by greater occurrence of symmetry/ordering compulsions . . . and that OCD patients with hoarding compulsions may have unique neuronal correlates and a poorer response to serotonin-reuptake inhibitors.?

According to Dr. Matsunaga, subtyping of OCD symptoms may be useful when developing the Diagnostic and Statistical Manual of Mental Disorders, 5th ed (DSM-V).

Although no systematic studies have been done in Japan, it is estimated that the prevalence of OCD in that country is similar to that reported in Western countries, said Dr. Matsunaga. "It's important to study OCD patients in different areas of the world," he said, adding that he would like to see more such research in Muslim countries.

Common Neurobiology

In an editorial accompanying the paper, Stefano Pallanti, MD, PhD, from the Mount Sinai School of Medicine, in New York, commented that in the Muslim culture, the term weswas refers to the devil as well as to an obsession, reflecting the religious connotation of the disorder in that culture.

Dr. Pallanti echoed the study conclusions, noting that despite Japan?s well-known cultural differences, the study results ?suggest that obsessive-compulsive disorder is more deeply embedded in common neurobiology than in cultural differences."

All authors report no competing interests. Supported in part by a grant from the Japanese Ministry of Education, Culture, Sports, Science, and Technology.

Am J Psychiatry. 2008;165:251-253 Abstract, 169-170. Abstract
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