The state wants to know whether the rapid expansion of casinos in the past five years has led to an increase in problem gamblers.
With five Maryland casinos and a sixth on the way, state-funded researchers said this week that they are preparing a survey to gauge how many people cannot control their gambling impulses in such a casino-rich region.
The survey will take place next year, after the $1.3 billion MGM National Harbor — scheduled to open in December — has been operating for six months.
"The state legislature wants to monitor the impact that the expansion of casino gambling is having on the state's population," said J. Kathleen Tracy, research director for the Maryland Center of Excellence on Problem Gambling, which is overseeing the survey.
Problem gambling is a psychiatric disorder. Its features, according to the center, include a need to bet more money more often and "restlessness or irritability" when trying to stop.
The survey will update research released in 2011 by the University of Maryland, Baltimore County that was designed to establish a baseline. That data was compiled from telephone surveys around the time the Hollywood Casino Perryville became Maryland's first casino in 2010.
Maryland is now among the country's most saturated gambling markets. Its five casinos have combined in recent months to generate record revenues, topping $100 million a month for the first time this spring.
The UMBC study estimated that about 150,000 Maryland adults — 3.4 percent of those who had ever gambled — experienced moderate to severe difficulties stemming from their gambling. The number of "at-risk" gamblers was estimated at 397,900, or about 9 percent.
The study was mandated by the 2007 law authorizing slot machines in the state if approved in a voter referendum. As part of the law, the Department of Health and Mental Hygiene was required to assess how many people gambled and the extent of gambling problems.
The new study is expected to be released by early 2018. The initial study cost about $500,000, and researchers expect this one to cost about the same.
"I'm going to be very interested in the findings — which groups are affected, age groups, gender, cultural groups, economic groups," said Lori Rugle, program director of the problem gambling center, part of the University of Maryland School of Medicine.
Lower-income people were found in the 2011 study to have a higher chance of being problem gamblers.
Maryland's casinos say they support the state's efforts to encourage responsible gambling. The programs include a confidential phone line (1-800-GAMBLER) for referrals to local help groups or counselors.
Under a state "voluntary exclusion program" established in 2011, problem gamblers can ban themselves from casinos, risking a trespassing citation for violations. The program has 1,207 participants.
The 2011 rates for problem gamblers in Maryland appear similar to those in other states, said Jan Jones Blackhurst, an executive vice president at Caesars, which owns the Horseshoe Casino Baltimore.
"Remarkably, it's pretty standard," she said. "It's always around the same."
She said Caesars, which has done advertising about responsible gambling, supports the new study and "any of that research becomes very valuable, not only for the states but for the operators."
Experts say it is not known whether more casinos mean more people with gambling problems.
"There have been very few repeat prevalence studies done," Rugle said. "Some variables are what kinds of efforts are out there for prevention and public awareness and treatment."
In the previous study, more than 56,000 Marylanders were called at random on their home phones, producing a sample size of 5,975 surveys.
This time, researchers face a challenge because people have moved away from use of land lines, Tracy said.
"We need to try to have a similar sample size," she said. "We may need to make vastly more phone calls to get to the same sample size."