– The tequila sure looks real, so do the beer taps. Inside the hospital at the National Institutes of Health, researchers are testing a possible new treatment to help heavy drinkers cut back — using a replica of a fully stocked bar.

The idea: Sitting in the dimly lit bar-laboratory should cue the volunteers' brains to crave a drink, and help determine if the experimental pill counters that urge.

These bottles are filled with colored water. The real alcohol is locked in the hospital pharmacy, ready to send over for the extra temptation of smell — and to test how safe the drug is if people drink anyway.

"The goal is to create almost a real-world environment, but to control it very strictly," said lead researcher Dr. Lorenzo Leggio, who is testing how a hormone named ghrelin that sparks people's appetite for food also affects their desire for alcohol, and if blocking it helps. Initial safety results are expected this spring.

Amid all the yearly resolutions to quit, alcohol use disorders affect about 17 million Americans, and only a small fraction receives treatment. There's no one-size-fits-all therapy, and the NIH is spurring a hunt for new medications that target the brain's addiction cycle in different ways — and to find out which options work best in which drinkers.

"Alcoholics come in many forms," explained Dr. George Koob, director of NIH's National Institute of Alcohol Abuse and Alcoholism, which has published new online guides, at www.niaaa.nih.gov.

What's the limit? NIAAA says "low-risk" drinking means no more than four drinks in any single day and no more than 14 in a week for men, and no more than three drinks a day and seven a week for women.

Treatment can range from inpatient rehab and 12-step programs to behavioral therapy and medications. Yet a recent review for the Agency for Healthcare Research and Quality estimated that less than a third of people who need treatment get it, and of those, less than 10 percent receive medications.

Three drugs are approved to treat alcohol abuse. One, naltrexone, blocks alcohol's feel-good sensation by targeting receptors in the brain's reward system — if people harbor a particular gene. The anti-craving pill acamprosate appears to calm stress-related brain chemicals in certain people. The older Antabuse triggers nausea and other aversive symptoms if people drink while taking it.

"Our hope is that down the line, we might be able to do a simple blood test that tells if you will be a naltrexone person, an acamprosate person, a ghrelin person," Koob said.