Adolescence is a critical stage of brain maturation. It performs important plastic and dynamic processes, in different brain regions that lead to the development of the adult brain.
Consumption of ethanol in adolescence alters brain plasticity and causes structural and functional changes in immature brain areas (prefrontal cortex, limbic system), which lead to cognitive and behavioral deficits.
These changes, along with sex hormone secretion and stress-related ones, can affect self-control, decision-making, and risky behaviors that contribute to anxiety and the onset of abusive alcohol use.
Teens may experience the risk and reward it differently than adults. Especially in conditions of greater emotional arousal. This makes teens more vulnerable in making decisions in stress disorders.
If we delve into the usual behaviour of these young people, 38% of girls and 43% of boys show abusive consumption of alcohol. These behaviors occur mainly during weekends and holidays. That’s why we wonder what genetic and psychological factors are involved in alcohol abuse during this stage.
Psychological factors for adolescent alcohol use
Adolescence is generally considered a stressful stage. During this period, young people exhibit certain common behaviors, such as depression, difficulty sleeping, emotional problems, anxiety, and shyness.
In addition, stressors in adolescents cause neurobehavioral and hormonal responses that vary compared to adult individuals. For example, stress causes plasma levels of corticosteroids (a hormone associated with stress) to stay elevated for longer in adolescents than in adults.
All of these psychological effects, typical of this age, are associated with changes in brain maturation during the transition from childhood to adulthood. The maturation of the brain’s prefrontal cortex ends at age 23 or 24 and controls certain impulses and behaviors such as attention.
Thus, the poor development of the prefrontal cortex in the brain leads adolescents to be impulsive and to acquire risky behaviors, such as abusive use of alcohol and other drugs.
However, this is one of many other factors. Environmental factors, i.e. those that are part of the environment, such as family, social relations with friends, etc., also have a great influence.
This is how genetics intervenes in alcohol addiction
In addition to psychological factors, genetic factors are also involved in alcohol abuse and addiction to certain drugs. In fact, according to several studies, the children of alcoholic parents are more likely to develop addictive behavior.
To this day, a gene that is directly associated with alcoholism has not been found. However, genes associated with different variants of enzymes that metabolize alcohol at the liver level have been found: alcohol dehydrogenase and aldehyde dehydrogenase.
These enzymes accelerate alcohol metabolization and reduce alcohol addiction risk. That is, these people would be less at risk for alcoholism because blood alcohol levels would not increase excessively.
Similarly, other genes that are associated with neural receptors (such as GABA and cholinergic) have been found on chromosomes of people with alcohol abuse. Variations in its expression appear to be associated with alcohol dependence.
In addition to the above variants, epigenetic changes (modifications in the expression of genes that are not due to an alteration of the DNA sequence and that are inheritable) may also intervene in the risk of alcoholism.
For example, a correlation between alcohol consumption and a chemical reaction (histone acetylation) has been shown in brain regions that are associated with addictive behaviors.
Why are these epigenetic changes?
It has recently been observed in mouse models that one of the causes involved in epigenetic changes could be the inflammatory immune response.
Alcohol is a neurotoxic substance that, when consumed in high amounts by adolescents, is able to activate in the brain a type of immune system receptors called TLRs. The activation of these receptors results in the release of pro-inflammatory molecules.
It is important to note that when comparing the effects of alcohol in boys and girls, it is observed that the inflammatory response is greater in girls than in boys at the same levels of alcohol in blood and brain. These results suggest that girls are more vulnerable to the neurotoxic effects of alcohol.
Alcoholism slows electrical impulses in neurons
On the other hand, alcohol abuse, according to studies in mouse models, hinders the process of myelination in the brains of adolescents, whose function is to facilitate electrical impulses to be transmitted quickly and efficiently throughout neurons.
In fact, neuroimaging techniques have shown that young people who abuse alcohol show a reduction in certain brain regions, such as the prefrontal cortex and hippocampus, regions involved in important processes such as memory and learning.
From the above data, it can be concluded that adolescence is a period of brain maturation that encourages young people to acquire risky behaviors. In addition, certain psychological factors associated with adolescence (such as stress), molecular factors (such as activation of certain receptors in the brain) and the expression of certain genes, may encourage them to be more prone to drug use such as alcohol.
Consuelo Guerri, of the Prince Philip Research Center, has collaborated in the realization of this article.
María Pascual, Professor of Physiology and researcher in the cellular and molecular neuropathology of alcohol, Universitat de Valencia and José Miñarro, Professor of the Area of Psychobiology, University of Valencia
This article was originally published in The Conversation. Read the original.
