Cognitive effects?
Although the researchers did not find any sex effects, Dr. Pfefferbaum stressed that this doesn’t mean they do not exist. “We just may not have the power to see them,” he said.
The study did not look specifically at binge drinkers, defined as consuming five drinks in 2 hours for men and four drinks in 2 hours for women. Dr. Pfefferbaum noted that it is difficult to get “good quantification” of binge drinking. “We don’t have a fine enough grain analysis to separate that out,” he said.
Asked whether the altered FA trajectory in heavy drinkers affects cognition, Dr. Pfefferbaum said “those studies are still in progress,” with results hopefully available within about a year.
Dr. Pfefferbaum said he and his colleagues are continuing to follow these adolescents and hope to see if the altered FA trajectory in heavy drinkers returns to normal, adding: “The real question now is: If they stop heavy drinking, will they get back on track?”
This study is believed to be the first to suggest in vivo differential vulnerability in WM microstructure with respect to age, the authors note.
In addition to asking teens about their alcohol use, the clinician’s role should be to “counsel and refer,” said Dr. Pfefferbaum. He also suggested accessing resources from the National Institute on Alcohol Abuse and Alcoholism.
Important data, but several limitations
In an interview, Oscar G. Bukstein, MD, MPH, medical director of outpatient psychiatry service at Boston Children’s Hospital, and professor of psychiatry at Harvard Medical School, also in Boston, said the findings provide further evidence that alcohol affects the maturing brain.
This study, and others that have examined cannabis use, “show that you have a dynamically growing brain with certain sections, particularly in this case the anterior and middle corpus callosum, that mature later [and] that are more likely to be affected by early alcohol use,” said Dr. Bukstein, who was not involved with the research.
He stressed the importance of determining the mechanism involved and noted some study limitations. For example, the DTI technology used may “already be out of date,” he said.
Using older technology may have prevented finding an impact of heavy drinking on parts of the brain other than the anterior and middle corpus callosum, Dr. Bukstein noted.
Newer technology might provide “a finer-grain nonlinear voxel-wise analysis,” although using more updated scanning techniques may not have detected additional differences in study groups, he added.
Dr. Bukstein also noted that there were limitations: The study did not have “gradations,” but only looked at heavy drinking and no to low drinking. “You’d like to find out about kids who are somewhere in the middle.” It also didn’t determine a “cutoff” where deleterious effects of alcohol on the brain begin, Dr. Bukstein added.
Additionally, the study didn’t look at brain development outcomes in children with conditions such as depression and ADHD that are known to lead to substance use – something a larger study may have been able to do, he said.
Dr. Bukstein noted that a newer and much larger study, the Adolescent Brain Cognitive Development study, has begun assessing kids for risk factors such as substance use, starting at age 10 years.
The study was funded by grants from NIAAA and by the National Institute on Drug Abuse, the National Institute of Mental Health, the National Institute of Child Health and Human Development, and the Stanford Institute for Human-Centered Artificial Intelligence–AWS Cloud Credits for Research. Dr. Pfefferbaum reported receiving an NIAAA grant during the conduct of the study. Dr. Bukstein disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.