People who undergo gastric bypass surgery to lose weight are twice as likely to undergo inpatient treatment for alcohol abuse, compared to those who undergo Lap-Band weight loss surgery, according to a new study.

The Los Angeles Times reports that it was already known that gastric bypass surgery allows the body to absorb alcohol more quickly. This study shows for the first time that the surgery leads to an increased risk of alcohol abuse.

The findings were reported at the Digestive Disease Week meeting in Chicago.

The Swedish researchers examined medical records for 12,277 patients who underwent weight-loss surgery and compared them with records of 122,770 healthy people who did not undergo the surgery. Before the surgery, weight-loss surgery patients were much more likely than their healthy counterparts to have been treated for alcoholism, depression, attempted suicide and psychosis, the newspaper reports.

Gastric bypass surgery creates a smaller stomach pouch, bypassing part of the intestines. During Lap-Band surgery, an inflatable band made of silicon is placed around the stomach to restrict a person’s food intake, but food still passes through the entire stomach.

Dr. John Morton, a Bariatric Surgeon at the Stanford School of Medicine, told the newspaper that normally, alcohol is at least partly broken down by enzymes in the stomach. When a person has gastric bypass surgery, this enzyme breakdown does not occur, so that when the alcohol reaches the intestines it is still mostly intact. The interior surface of the intestines contains finger-like structures called villi, which Dr. Morton explains absorb alcohol very efficiently. This  means that alcohol levels reach high concentrations in the blood more quickly.