Binge drinking and alcoholism are serious disorders where people consume too much alcohol, drinking to the point of sickness or becoming emotionally dependent on alcohol. Around 10 percent of all people who drink alcohol develop drinking problems. A new study done at UCSF used mice to show that one reason some people might develop drinking problems could be caused by a piece of our genetics known as microRNA.

The study was published in the journal Molecular Psychiatry.

The research team at UCSF did previous research showing that when people drink moderately, it increases the amount of a protein in the brain called brain-derived neurotrophic factor, or BDNF. Higher levels of BDNF were associated with less risk for alcoholism and other disorders involving excess use of alcohol. BDNF seemed to help protect people against drinking excessively.

However, the study showed that when mice drank too much alcohol, similarly to when humans binge drink, their levels of BDNF decreased, lowering their protection against alcohol.

The way the BDNF levels ceased to function in mice who drank excessively seemed to be related to an increase in microRNA that happened in conjunction with the decreased BDNF levels. MicroRNA is a type of RNA that does not code genes, but influences the way genes express themselves.

"Our results suggest BDNF protects against the transition from moderate to uncontrolled drinking and alcohol use disorders. When there is a breakdown in this protective pathway, however, uncontrolled excessive drinking develops, and microRNAs are a possible mechanism in this breakdown," said Dorit Ron, the lead author of the study.

Ron said that this microRNA process might be one of the reasons why people develop alcohol use disorders like alcoholism, while 90 percent of drinkers are able to consume alcohol on a casual basis. He suggested that focusing on this molecule might yield good results for helping to find treatment for alcohol disorders.

This study could provide an important starting point for treating alcoholism by treating a biological mechanism. Current forms of treatment are tricky, because they decrease the total amount of pleasure experienced. This study might shed light on a way to treat alcoholism without reducing pleasure.

"In searching for potential therapies for alcohol abuse, it is important that we look for future medications that target drinking without affecting the reward system in general. One problem with current alcohol abuse medications is that patients tend to stop taking them because they interfere with the sense of pleasure," said Ron.