ROANOKE TIMES
Copyright (c) 1996, Roanoke Times
DATE: Friday, November 29, 1996 TAG: 9611290123
SECTION: NATIONAL/INTERNATIONAL PAGE: A1 EDITION: METRO
DATELINE: WASHINGTON
SOURCE: ASSOCIATED PRESS
Scientists for the first time have identified a personality gene that seems to influence whether a person will be a hand-wringing worrier or a self-assured warrior.
The gene can act like natural Prozac in the brain, enhancing self-confidence and contributing to a cheerful temperament, according to a report in Friday's issue of the journal Science. But the researchers found that most people inherit a different version of the gene that apparently has the opposite effect, predisposing them to mild but chronic anxiety.
If confirmed and extended in follow-up studies, the finding could shed light on the genetics of personality and facilitate development of better mood-altering medications. Already it has ignited a burst of speculation about why evolution might have favored individuals with an anxious bent.
The work is the latest in a string of recent efforts to find the genetic basis of complex behaviors - a new scientific specialty that has stirred controversy over its tentative findings of genes for homosexuality, alcoholism, manic-depression and ``novelty-seeking.''
Virtually all those findings have crumbled upon further analysis. And experts cautioned that the new gene, which in its most common form is linked to what psychologists call ``neuroticism,'' could easily succumb to the same fate.
But several researchers said they were inclined to believe the new results, given that the gene in question is known to regulate serotonin - the same brain chemical targeted by the antidepressant Prozac.
Others said the report appeared appropriately modest in its conclusion that the gene accounts for only about 4 percent of the difference between chronically anxious people and those who stride through life with cheerful aplomb. The rest of the difference, scientists believe, is due to a dozen or more still-unidentified genes and a host of environmental factors, including parenting practices, that are as important as all those genes combined.
``Studies of twins that measure the influence of genes and environment on personality show that each contributes about 50 percent,'' said David Goldman, chief of the laboratory of neurogenetics at the National Institute of Alcohol Abuse and Alcoholism in Rockville, Md.
The new study, led by Klaus-Peter Lesch of the University of Wuerzburg in Germany, in collaboration with scientists from the U.S. National Institutes of Health, focuses on a gene that regulates a kind of molecular pump that in turn affects brain levels of serotonin, a chemical messenger known to affect mood and personality.
Dean H. Hamer, a National Cancer Institute researcher who helped conduct the study, emphasized that many other factors contribute to personality and the gene findings are true only on average. ``This gene is not their fate,'' he said.
Moreover, Hamer said, the correlation relates only to ``garden-variety anxiety and depression,'' not serious disorders such as clinical depression. And he noted that the study was conducted almost exclusively on men, about half of them gays who had already been recruited for another study. Although results did not differ between homosexual and heterosexual participants, it is uncertain whether the study's conclusions apply to women.
If the findings hold up, however, scientists will have to answer a difficult question: Why has a genetic variant that predisposes to anxiety persisted through evolution in a majority of the population?
``There may be some useful things about being somewhat more anxious as long as it's within a normal range,'' said Dennis L. Murphy, chief of the National Institute of Mental Health's laboratory of clinical science and a collaborator on the new research.
``Maybe the fearful ones survived the eruption of Vesuvius,'' Goldman said, ``and the ones that were brave or stayed asleep got buried beneath tons of lava and ash.''
Perhaps the most alluring explanation for anxiety's persistence comes from Hamer at the NCI. One of Prozac's more common side effects is loss of libido. If serotonin's salutary effects on mood are linked to a dampening of eroticism, he speculates, then the reverse may also be true, and people who are anxious may tend to have more sex than their happier counterparts.
LENGTH: Medium: 79 linesby CNB