Most alcoholics start drinking during their teen years, but the disease can also strike those who begin using alcohol at a younger age — and the problem often goes unrecognized, experts say.

The San Francisco Chronicle reported July 16 that Mary Brennan of suburban Chicago began drinking at age 10 with friends of her older brother; by 15, she was bringing vodka to school in Gatorade bottles and getting drunk every day. Her father, a single parent, didn’t recognize the problem, even after she overdosed and nearly died.

The underage-drinking rate in the U.S. has remained steady in recent years, but some research indicates that youths are starting to drink at a younger age. One study, from the Partnership for a Drug-Free America, concluded that about 10 percent of nine-year-olds had consumed more than a sip of alcohol. And research from the National Institute on Alcohol Abuse and Alcoholism indicates that children who begin drinking before age 15 are four times more likely to have drinking problems than those who start drinking at age 21 or later.

“A third of kids ages 12 to 17 had their first drink before 13,” said Susan Foster, director of policy research for the National Center on Addiction and Substance Abuse (CASA) at Columbia University. “That’s about 6.4 million kids, many more than there have been historically. Very young drinkers are a huge concern.”

“We’ve received calls from parents of kids as young as 8,” said Cole Rucker, CEO and cofounder of the Echo Malibu treatment center. “Every year, alcohol use shows up in younger and younger kids.”

Young drinkers often get started with alcohol use by getting drinks from friends or family liquor cabinets. Polls have shown that youths ages 13 and up say it is easy to get alcohol from adults — and sometimes their own parents, who may themselves have drinking problems.

“The traditional thinking is that risk factors for alcohol abuse show up in adolescence,” said Robert A. Zucker, Ph.D., director of the Addiction Research Center at the University of Michigan. “But, actually, they can show up earlier — in children 9 or younger, even in preschoolers.”

Few treatment programs exist for very young alcoholics, who rarely get adequate services, such as intensive inpatient care.