ANOTHER WORRY ABOUT ANXIETY - IT MAY BE HEREDITARY.

Byline: Denise Mann Medical Tribune News Service

People who fear that they will grow up to be as neurotic under stress as one of their parents may have reason to fret.

New research shows that a certain genetic variation may make a person more prone to anxiety.

In two studies with a total of 505 people, some of whom were siblings, researchers found that having a certain variation of a gene that helps control levels of the brain chemical serotonin may affect anxiety levels.

Serotonin has long been thought to play a role in anxiety, they noted in the study, published in the journal Science.

In the study, people who had a short form of the gene were more likely to become anxious in the face of stress, according to the researchers. On the other hand, people with a long form of the gene were more likely to be easygoing and resilient to stress.

The new research suggests that genetic variations may play a role in the development of certain personality traits, said researcher Dr. Benjamin Greenberg, a senior clinical investigator at the National Institute of Mental Health in Bethesda, Md.

Greenberg estimated that the newly identified genetic variation probably accounts for about 4 percent of all of the genetic and environmental factors that influence personality. About 40 percent to 60 percent of personality traits are thought to be inherited.

``Personality is determined by a lot of different things and they all add up to produce a pattern,'' he said.

While preliminary, ``this is a very important finding in the tradition of other findings suggesting that personality traits do run in families,'' said Dr. Eric Hollander, director of Compulsive, Impulsive and Anxiety Disorders Program at Mount Sinai School of Medicine in New York.

To arrive at their findings, Greenberg and colleagues performed genetic screening tests on the 505 study participants. Then they administered two standard personality tests to determine whether variations in the gene were linked to personality traits.

The findings most likely apply only to general anxiety, not anxiety disorders, Greenberg said. ``The role of the short variant in such disorders and in how individuals with the different forms of this variation would respond to treatment with antianxiety and antidepressant drugs remains to be studied,'' Greenberg said.

Antidepressants known as selective serotonin reuptake inhibitors (SSRIs) including Prozac and Zoloft are commonly prescribed to treat anxiety disorders. These medications act by increasing available levels of serotonin in the brain.

By gaining a better understanding of how the new genetic variation affects a person's ability to handle stressful situations, doctors may one day be able to help prevent the development of anxiety disorders in very anxious individuals, said Dr. David Goldman, chief of the laboratory of neurogenetics at the National Institute of Alcohol Abuse and Alcoholism in Rockville, Md.

``It is an enormously interesting'' finding, but until more studies confirm these findings, it would be a mistake to draw many conclusions, Goldman added.