Prenatal alcohol dependency

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Prenatal alcohol linked to slower cognitive skills

A new study links moderate to heavy prenatal alcohol exposure to slower cognitive processing speeds and lower cognitive processing efficiency in children compared with unexposed children.

Dr. Matthew Burden (PhD), a postdoctoral research fellow at Wayne State University school of medicine here led a study of 337 children from the Detroit Prenatal Alcohol Longitudinal Cohort. Maternal alcohol use data had been collected for this cohort during prenatal visits.

Effects persist

The children were 7.5 years old at the time of assessment. The results indicate lasting effects of prenatal alcohol exposure on cognitive processing. These effects tended to fall on a continuum that corresponded to level of exposure.

"It's on a continuous scale, so it's kind of a dose-response model," Dr. Burden said.

The children were assessed for processing speed and efficiency on the basis of four tasks representing different cognitive functions.

A fifth task-identifying different colours that appeared in a long row-provided a reaction time for comparison purposes. "The colour naming is just one simple reaction time task," he said.

The other tasks-such as determining which of two numbers is larger, or whether a single digit appeared in a short number sequence displayed immediately before-require processing before the reaction.

Gap in reaction times

"The distinction is between the speed it just normally takes to make a response, and the speed it takes as a task becomes progressively difficult," Dr. Burden said.

"As the problem gets harder, there is a greater degree of slowing down. And you would expect some of that, but there's even more slowing for the kids with the heaviest exposure."

The range of reaction times becomes wider as the tasks become more complex, with children who had higher prenatal alcohol levels scoring at the higher end of the reaction time spectrum.

In order to be certain that the measured effects were the result of prenatal alcohol exposure, Dr. Burden and his colleagues controlled for 23 potentially confounding variables, ranging from socioeconomic status and gender to postnatal lead exposure and maternal depression. Current maternal alcohol consumption was another potential confounder.

"These things are related-a lot of people who drink during pregnancy also continue to drink heavy amounts later," Dr. Burden said. "But this effect is really specific to prenatal exposure, because the effect persists after you control for current alcohol."

No safe level

The take-home message from these data is that pregnant women should not drink, Dr. Burden said, adding that the National Institute on Alcohol Abuse and Alcoholism (NIAAA) supports that idea.

"That's really what NIAAA is saying-there's really no safe level for drinking during pregnancy that's been established, and the effects tend to happen on a continuum of exposure."

Parental alcohol dependency puts children at risk for substance abuse

Parental alcohol dependency represents a risk for maladaptive behaviours in adulthood that extend beyond alcohol dependency and into illicit drug use, according to researchers at the University of North Carolina and Arizona State University. Parental alcohol dependency has been associated with both early onset of drinking and persistent alcohol abuse throughout adulthood.

The study followed 545 adolescents over 15 years, looking for differences in patterns of drug experimentation and drug use into early adulthood between children of parents with alcohol dependency and children whose parents did not have a problem with alcohol. The study found that children whose parents had a problem maintained consistent levels of drug use, such that by age 25-30, their level of drug use was substantially higher than that of children whose parents did not have a drinking problem.

The study results indicate that as a consequence of parental alcohol dependency, children of these parents did not follow the typical trend by which individuals are expected to decline in drug use before age 30. In order to test mediational models, the researchers looked at marriage and its effect on declines in drug use. For all children, marriage was associated with lower levels of drug use. However, since children of parents with alcohol dependency were less likely to be married, they were more likely to have continued elevated levels of drug use in young adulthood.