The researchers at the University of Aahus, the University of Bonn and the University of Giessen in Germany and Vanderbilt University in Nashville suggest inborn differences affecting the brain neurotransmitter dopamine may be among the biological and environmental factors linked to anxiety disorders.
The study involved 96 women participants -- averaging 22 years old -- recruited from the Giessen Gene Brain Behavior Project. Women carrying two copies of a gene showed a stronger "startle" reflex when viewing unpleasant pictures and exhibited greater anxiety on a personality test.
This wariness, the researchers suggest, may have been adaptive since being anxious in dangerous environments may have been an advantage.
"This single gene variation is potentially only one of many factors influencing such a complex trait as anxiety. Still, to identify the first candidates for genes associated with an anxiety-prone personality is a step in the right direction," study co-author Christian Montag of the University of Bonn says in a statement.
The study is published in Behavioral Neuroscience,
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