Updated

Researchers say there may be a link between estrogen deficiency and obsessive-compulsive disorder (OCD) in men.

More than 3 million U.S. adults have OCD, says the National Institute of Mental Health. The disorder involves recurrent, unwanted thoughts or rituals such as counting, checking, cleaning, or washing the hands, which people feel they cannot control.

People with OCD can suffer intensely, but treatment is available. It's important to get help as soon as possible to improve quality of life.

Read Web MD's "More About Obsessive-Compulsive Disorder."

OCD Behaviors Resolve With Estrogen

The findings are based on experiments with lab mice, not people.

Some of the mice in the study had a normal set of genes. Others were bred not to make an enzyme called aromatase, which converts male sex hormones to the female sex hormone estrogen. Because the genetically altered mice couldn't make aromatase, they had less estrogen than normal mice.

The results were presented in San Diego at The Endocrine Society's annual meeting.

The estrogen-deficient male mice stood out from the other mice in three ways:

—They ran "excessively" on their running wheels.

—They spent twice as long grooming themselves after being misted with water, compared with the other male mice.

—They had lower levels of a brain chemical called COMT (catechol-O-methyl transferase).

Read Web MD's "Obsessive Compulsive Disorder Runs in Families."

The extreme grooming and running patterns are two indicators of OCD in mice, and low COMT levels have been found in obsessive-compulsive men, say the researchers.

Treatment with estrogen reversed the excessive running and grooming behavior as well as raised COMT levels.

Estrogen-deficient female mice did not show the same patterns. That provides "further evidence" that estrogen affects the brains of males and females differently, say the researchers.

Read Web MD's "Cleanliness Rules Germaphobes' Lives."

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By Miranda Hitti, reviewed by Michael W. Smith, MD

SOURCES: The Endocrine Society's Annual Meeting, San Diego, June 4-7, 2005. News release, The Endocrine Society. National Institute of Mental Health: "Facts About Obsessive-Compulsive Disorder." WebMD Medical Reference from Healthwise: "Obsessive-Compulsive Disorder (OCD) — Topic Overview." WebMD Medical Reference from Healthwise: "Obsessive-Compulsive Disorder (OCD) — When to Call a Doctor."