Binge drinking as a teenager can cause long-lasting damage to the brain well into adulthood, a new study has warned.
This is because drinking excessive amounts of alcohol when young can damage the brain and cause permanent changes to DNA.
Alcohol changes genes in brain cells, which stop the cells developing connections between them, altering behaviour, they said.
However, they discovered a cancer drug may reverse the damage.
Professor Subhash Pandey, of the University of Illinois College of Medicine, explained that binge drinking during the teenage years disrupts the brain's normal development.
He said: 'Our study provides a mechanism for how binge-drinking during adolescence may lead to lasting changes that result in increased anxiety and alcoholism in adults.'
Intermittent alcohol exposure 'degrades the ability of the brain to form the connections it needs to during adolescence, he explained.
'The brain doesn't develop as it should, and there are lasting behavioural changes associated with this,' he added.
As part of the study, Professor Pandey and his team carried out lab experiments on 28-day-old rats to investigate how alcohol would affect their brain development.
They were given alcohol for two days on, then two days off, which was repeated over 13 days.
Rats exposed to alcohol showed changes in behaviour that lasted into adulthood, long after the exposure to alcohol ended.
They showed increased anxiety-like behaviours and drank more alcohol in adulthood.
When brain tissue from the area of the brain called the amygdala was examined, rats given alcohol showed changes to their DNA, known as epigenetic changes.
Professor Pandey explained that epigenetic changes are chemical modifications of DNA, or of the proteins around which DNA is wound, like thread on a spool.
Modification of these proteins, which are called histones, can change how loosely or tightly the DNA is wound.
THE YOUNG PROFESSIONALS ADDICTED TO ALCOHOL: A FIFTH OF WORKERS NOW BELIEVE THEY HAVE A DRINKING PROBLEM
Many of us enjoy a chilled glass of wine or a cold beer after a hard day at work.
But while the majority of people believe their drinking habits are under control, one in five young professionals now considers themselves to have a problem with alcohol, a survey found.
A new poll laying bare the public's attitudes to drinking found nearly half of young workers think it is acceptable to regularly get drunk on a night out, compared to a fifth of the general population.
It also revealed the risky effects of drinking, as young people admitted to forgetting how they got home, driving themselves home drunk or getting in a car with someone they knew was intoxicated.
Genes that lie within DNA that is tightly wrapped around the histones are less active than if the DNA is loosely wrapped.
The looser the DNA is coiled, the more accessible the genes are to the cellular machinery that 'expresses' them.
The rats exposed to alcohol had more tightly coiled DNA.
They also had increased levels of a protein called HDAC2, which modifies histones, causing DNA to be wound tighter around them.
These epigenetic changes were linked to lowered expression of a gene that nerve cells need in order to form new connections between cells, known as synaptic connections.
Professor Pandey argued the lowered activity of this gene may be due to the tighter winding of its DNA.
The lower activity of the gene persisted in adulthood, even if alcohol exposure was stopped weeks before.
The researchers also observed diminished connectivity between nerves in the amygdalae of these affected adult rats.
But a cancer drug known to block the activity of HDAC2 could be used to treat them, he said.
In his experiments, the drug restored expression of the gene needed for synapse formation and the rats' DNA was observed to be less tightly coiled.
The effect of this was that the rats exhibited less anxiety and reduced alcohol intake.
Professor Pandey added: 'We aren't sure if the drug needs to be given long term during adulthood in order to completely reverse the harmful effects of adolescent alcohol exposure.'
The findings were reported online in the journal Neurobiology of Disease.
Culled: Ukdailymail