Updated

Preschool has surprisingly enduring benefits lasting well into adulthood, according to one of the biggest, longest follow-up studies of its kind.

Better jobs, less drug abuse and fewer arrests are among advantages found in the study that tracked more than 1,000 low-income, mostly black Chicago kids for up to 25 years.

Michael Washington was one of them. Now a 31-year-old heating and air conditioning contractor, Washington attended a year of preschool at Chicago's intensive Child-Parent Center Education Program when he was 4.

The ongoing publicly funded program focuses on language development, scholastic skills and building self-confidence. It involves one or two years of half-day preschool, and up to four additional years of educational and family services in grade school. Preschool teachers have college degrees and are certified in early childhood education, and parents are encouraged to be involved in the classes.

Washington lived in an impoverished West Side community and has strong memories of preschool field trips to the library, zoo and planetarium where he learned to love science. He says he'll never forget the strong influence of his preschool teachers.

"You expect your mom and dad to care for you. But when a stranger, who has no ties to you whatsoever, takes the time to invest in you, takes the time to listen, that makes you open your eyes bigger," said Washington, now living in Blue Island, Ill. "It was real cool."

Washington got good grades in elementary and high school, and attended two years of college at Chicago State University. Unlike other kids he knew from the neighborhood who didn't attend preschool, he says he never tried drugs and was never arrested.

The study tracked nearly 900 children into adulthood who attended the program in the early 1980s, and compared them to almost 500 low-income Chicago youngsters, most of whom didn't attend preschool.

The results were published Thursday in the online version of the journal Science. They bolster findings from similar, smaller studies and show that high-quality preschool "gives you your biggest bang for the buck," said Dr. Pamela High, chair of an American Academy of Pediatrics committee that deals with early childhood issues. She was not involved in the study.

Though many preschool kids also got extra services in grade school, including intensive reading instruction, the researchers found the most enduring effects, particularly for non-academic success, were due to one or two years of preschool. The authors theorize that those intensive early childhood experiences built intellectual skills, social adjustment and motivation that helped children better navigate their high-risk environments.

To be sure, the challenges facing the children in both groups were still insurmountable to many. As adults, the average annual income for those who went to preschool is less than $12,000 and almost half of them had been arrested as adults. As dismal as those outcomes, the numbers were still better than for the group that didn't attend preschool. And experts not involved in the study called the results impressive.

"To still show really any advantage for such a long period of time is remarkable and noteworthy," said Kyle Snow, director of the National Association for the Education of Young Children's applied research center.

The study's lead researcher, Arthur Reynolds of the University of Minnesota, said the differences between the groups are meaningful and translate to big savings to society for kids who attended preschool.

The average cost per child for 18 months of preschool in 2011 is $9,000, but Reynolds' cost-benefit analysis suggests that leads to at least $90,000 in benefits per child in terms of increased earnings, tax revenue, less criminal behavior, reduced mental health costs and other measures, he said.

"No other social program for children and youth has been shown to have that level of return on investment," he said.

Among the study results:

— 80 percent of the preschool group finished high school versus 75 percent of the others;

— Nearly 15 percent of the preschool group attended a four-year college, versus 11 percent of the others;

— 28 percent of the preschool group had skilled jobs requiring post-high school training versus 21 percent of the others;

— Average annual adult income for the preschool group was about $11,600 versus $10,800 for the others. The low average incomes include zero earnings for those in prison and close to that for adults who were still in college or studying elsewhere.

— 14 percent of the preschool group had abused drugs in adulthood versus 19 percent of the others;

— 48 percent of the preschool group had been arrested in adulthood and 15 percent had been incarcerated, versus 54 percent of the others arrested and 21 percent incarcerated.

The results are based on public records, administrative data and interviews with study participants.

A spokeswoman for Chicago's public schools noted that newly elected Mayor Rahm Emanuel committed during his campaign to ensuring that the city's highest-risk kids have access to early childhood programs.

And despite cuts to state early childhood funding, public preschool and kindergarten programs in Chicago have not been slashed for next year, she said.

___

Online:

Science: http://www.scienceexpress.org

___

AP Medical Writer Lindsey Tanner can be reached at http://www.twitter.com/LindseyTanner