Sober N Clean

Researchers at the UIC College of Medicine and the Jesse Brown VA Medical Center have discovered a molecular basis for the link between anxiety and alcoholism. This discovery may help develop a new therapeutic approach for the treatment and control of alcohol addiction.

"The association of anxiety with increased alcohol use is a key factor in the initiation and maintenance of alcohol addiction," said Dr. Subhash Pandey, UIC professor of psychiatry and director of neuroscience alcoholism research, lead author of the study, and "this is the first direct evidence of the molecular processes occurring in the neurons that is responsible for the co-morbidity of anxiety and alcoholism." People with high levels of anxiety are more likely to become addicted to alcohol because alcohol can temporarily decrease anxiety. Also, frequent consumers often feel extreme anxiety during withdrawal of alcohol.

"Alcoholics may feel a need to continue to drink alcohol in an attempt to self-medicate to reduce their anxiety and other unpleasant withdrawal symptoms," explained Pandey. Initial use of alcohol often relieves anxiety, and after repeated exposure to alcohol, people may feel the need to consume alcohol in order to feel normal.

Experimentation with laboratory animals led to the finding of a protein within neurons in the amygdala that affects alcohol withdrawal symptoms. The amygdala is the area of the brain associated with emotion and anxiety. When the shape of these neurons are changed, communication between the neurons is affected which leads to behavior changes.

To communicate, neurons send signals through branches called dendritic spines, and the researchers discovered that short-term alcohol exposure led to an increase of these branches in certain regions of the amygdala. The increase of dendritic spines creates anti-anxiety effects by producing a certain protein called Arc in response to a nerve growth factor called BDNF.

BDNF is stimulated by alcohol exposure. Animals dependent on alcohol eventually developed a tolerance to the lowering of anxiety from alcohol consumption. When alcohol was withheld from these dependent animals they developed high anxiety, and levels of BDNF and Arc were decreased in the amygdala. The researchers eliminated the anxiety by raising BDNF and Arc back to normal levels. Tests showed a relation between lowered levels of BDNF and Arc in the amygdala and increased anxiety.

This discovery "[can] be used to identify new targets for developing medications that alleviate withdrawal-induced anxiety and potentially modify a motivation for drinking," said Antonio Noronha, director of neuroscience and behavior research at the National Institute on Alcohol Abuse and Alcoholism.

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