Dr. Roh-Yu Shen and researchers at the State University of New York at Buffalo reported that part of the brain damaged by alcohol before birth involves a complex communication system between nerve cells.
"We have found that the electrical activity of... dopamine neurons in the brain is reduced in the offspring of pregnant rats treated with alcohol," Shen told Reuters Health in an interview. "These neurons normally generate a certain amount of spontaneous electrical activity... resulting in dopamine release in brain areas... responsible for attention."
Reduced Activity
Dopamine is one of a number of natural chemical substances called neurotransmitters that help transmit impulses across the synapse, or gap, between nerve cell endings."We think that attention-hyperactivity problems... may be caused by the reduced activity in (these) dopamine neurons," Shen explained. She observed no structural differences in the areas where these neurons are situated, no loss or destruction of neurons, but rather "reduced activity" of the cells in both young and adult animals.
Shen said "alcohol exposure impairs the development of brain dopamine neurons." This impairment "ultimately results in a decrease in the quantity of dopamine released in areas of the brain that control attention and the ability to focus."
Beyond Childhood
The new study results strongly suggest that "substances of abuse could lead to mental deficits that continue beyond childhood." Shen said, "clinicians might want to reexamine the notion that ADHD may be 'outgrown' (since) a reduced dopamine function is a persistent phenomenon during adulthood. It may simply take a more subtle form.""The rat model provides us with a systematic approach to investigate the therapeutic potential of various pharmacologic agents in ADHD following fetal alcohol exposure." She cited Ritalin as an example of a stimulant drug whose properties may be useful in treating alcohol-induced ADHD.
Alcohol is not the only culprit. Substances such as cocaine and certain psychiatric medications also reduce dopamine neuron activity, she said, and "any events that disrupt dopamine neurons during fetal development, for example, stress, could lead to dysfunction of neurons and ADHD."
More Information
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FAQ About ADD
Probably the single most informative page on the Internet about Attention Deficit Disorder, from About.com ADD Guide Eileen Bailey.
Pregnancy Resources
Find a wealth of information and resources about pregnancy at the About.com Pregnancy site, from your Guide Robin Weiss.
Alcohol and Pregnancy
Some experts say moderate drinking during
pregnancy is okay, but there are others who believe taking even one
drink is like playing Russian Roulette with your baby's health.
Issues for Women
Women who abuse alcohol, or even occasionally drink to excess, face greater risks to their health than their male counterparts.
Fetal Alcohol Syndrome
Other risks of drinking while pregnant.
