Binge drinking in adolescence may increase risk for anxiety later in life

March 11, 2019

Science Daily/University of Illinois at Chicago

Researchers have found that adolescent binge drinking, even if discontinued, increases the risk for anxiety later in life due to abnormal epigenetic programming.

A growing body of evidence supports the idea that alcohol exposure early in life has lasting effects on the brain and increases the risk of psychological problems in adulthood. Now, researchers at the University of Illinois at Chicago have found that adolescent binge drinking, even if discontinued, increases the risk for anxiety later in life due to abnormal epigenetic programming. The findings of the study, which was conducted in animals, was published in the journal Biological Psychiatry.

"Binge drinking early in life modifies the brain and changes connectivity in the brain, especially in the amygdala, which is involved in emotional regulation and anxiety, in ways we don't totally understand yet," said Subhash Pandey, professor of psychiatry in the UIC College of Medicine, director of the UIC Center for Alcohol Research in Epigenetics and lead author of the study. "But what we do know is that epigenetic changes are lasting, and increase susceptibility to psychological issues later in life, even if drinking that took place early in life is stopped."

"Epigenetics" refers to chemical changes to DNA, RNA, or specific proteins associated with chromosomes that change the activity of genes without changing the genes themselves. Epigenetic alterations are required for the normal development of the brain, but they can be modified in response to environmental or even social factors, such as alcohol and stress. These kinds of epigenetic alterations have been linked to changes in behavior and disease.

Adolescent rats were exposed to ethanol (a type of alcohol) for two days on and two days off or to the same protocol using saline for 14 days. All rats underwent an assessment for anxiety.

Pandey and his colleagues exposed adolescent rats to a regimen designed to mimic binge drinking. Those rats exhibited anxious behavior later in life, even if the binge drinking regimen stopped in late adolescence and the rats were allowed to mature to adulthood without any further exposure to alcohol.

These rats also had lower levels of a protein called Arc in the amygdala. Arc is important for the normal development of synaptic connections in the brain. Rats with less Arc also had about 40 percent fewer neuronal connections in the amygdala compared with rats that weren't exposed to alcohol.

"We believe that the decrease in Arc levels is caused by epigenetic changes that alter the expression of Arc, and an enhancer RNA, which modifies the expression of Arc. These changes are caused by adolescent alcohol exposure," said Pandey.

"Exposure to alcohol causes epigenetic reprogramming to occur, leading to molecular changes in the amygdala, which are long-lasting, even in the absence of more alcohol," said Pandey, who is also a senior research career scientist at the Jesse Brown VA Medical Center. "If the amygdala has deficits in its wiring or connectivity, and these modifications are long-lasting, the individual is at risk for psychological issues based on difficulties in regulating emotions, such as anxiety or depression and the development of alcohol use disorder later in life."

https://www.sciencedaily.com/releases/2019/03/190311125156.htm

Brain growth inhibited by heavy alcohol use

April 1, 2019

Science Daily/Oregon Health & Science University

New research in nonhuman primates shows that heavy use of alcohol can actually slow the rate of growth in developing brains. The study, to be published April 1, in the journal eNeuro, shows that heavy alcohol use reduced the rate of brain growth by 0.25 milliliters per year for every gram of alcohol consumed per kilogram of body weight. In human terms, that's the equivalent of four beers per day.

Heavy use of alcohol among adolescents and young adults is not only dangerous in its own right, but new research in nonhuman primates shows that it can actually slow the rate of growth in developing brains.

The study, published today in the journal eNeuro, shows that heavy alcohol use reduced the rate of brain growth by 0.25 milliliters per year for every gram of alcohol consumed per kilogram of body weight. In human terms, that's the equivalent of four beers per day. The research involved rhesus macaque monkeys at the Oregon National Primate Research Center.

"Chronic alcohol self-intoxication reduced the growth rate of brain, cerebral white matter and subcortical thalamus," the researchers write.

Researchers measured brain growth through magnetic resonance imaging of 71 rhesus macaques that voluntarily consumed ethanol or beverage alcohol. Scientists precisely measured intake, diet, daily schedules and health care, thus ruling out other factors that tend to confound results in observational studies involving people. The findings in the study help validate previous research examining the effect of alcohol use on brain development in people.

"Human studies are based on self-reporting of underage drinkers," said co-author Christopher Kroenke, Ph.D., an associate professor in the Division of Neuroscience at the primate center. "Our measures pinpoint alcohol drinking with the impaired brain growth."

The new study is the first to characterize normal brain growth of 1 milliliter per 1.87 years in rhesus macaques in late adolescence and early adulthood. And it further reveals a decrease in the volume of distinct brain areas due to voluntary consumption of ethanol.

Lead author Tatiana Shnitko, Ph.D., a research assistant professor in the Division of Neuroscience at the primate center, said previous research has shown the brain has a capacity to recover at least in part following the cessation of alcohol intake. However, it's not clear whether there would be long-term effects on mental functions as the adolescent and young adult brain ends its growth phase. The next stage of research will explore that question.

"This is the age range when the brain is being fine-tuned to fit adult responsibilities," Shnitko said. "The question is, does alcohol exposure during this age range alter the lifetime learning ability of individuals?"

This study was funded by the National Institute on Alcohol Abuse and Alcoholism (U01 AA013510, P60 AA013510 and U24 AA025473.

https://www.sciencedaily.com/releases/2019/04/190401133019.htm

Is anxiety in childhood and adolescence linked to later alcohol use disorders?

March 20, 2019

Science Daily/Wiley

In an Addiction analysis of relevant published studies, investigators found some evidence for a positive association between anxiety during childhood and adolescence with later alcohol use disorders.

Approximately 43 percent of associations were positive, meaning that anxiety was associated with a higher likelihood of later alcohol use disorders; however, 11 percent of associations were negative, with anxiety being associated with a lower likelihood of later alcohol use disorders. Approximately 30 percent of associations were equivocal and 15 percent were unclassifiable based on the information reported.

The authors of the analysis noted that it is important to establish which anxious individuals consume more alcohol and develop alcohol use disorders in order to develop targeted interventions.

"The evidence from prospective cohort studies is suggestive but not conclusive of a positive association between anxiety during childhood and adolescence and subsequent alcohol use disorder," said lead author Maddy Dyer, of the University of Bristol, in the UK. "Associations of anxiety with later drinking frequency or quantity and binge drinking were inconsistent. Further research is needed to understand why there are differences in associations for consumption levels versus problematic use, and to determine which individuals with anxiety develop alcohol problems."

https://www.sciencedaily.com/releases/2019/03/190320102030.htm