Incarcerated juveniles and young adults take their own lives at much higher rates than other young people, but are far less likely to confide of their despair before they act or even to admit they are depressed.

Those are among the findings of a new study published in the May edition of the Journal of the American Academy of Child and Adolescent Psychiatry.

Researchers from Nationwide Children’s Hospital in Columbus, Ohio, said their results underscore the need for early suicide risk detection, and better suicide prevention and intervention efforts geared to incarcerated children and young adults.

The study is based on federal data about U.S. suicide deaths for 10- to 24-year-olds from 2003 to 2012 compiled by the National Violent Death Reporting System.

Only about 19 percent of the young people who killed themselves while in custody expressed any suicidal intent beforehand, compared with nearly 31 percent of young people in the general population. About a quarter of the incarcerated young people showed depressive symptoms before their suicides, less than the nearly 39 percent of young people in general.

Yet the incarcerated young people who took their own lives were not significantly different from their general population peers in terms of key suicide risk factors like a history of suicide attempts, mental health conditions, or alcohol and drug use, the researchers found. A little over 37 percent of all young people who killed themselves had some mental health problem, according to the study.

Donna Ruch, a scientist with the Center for Suicide Prevention and Research at Nationwide Children’s, said the researchers were surprised by the findings. That, she said, led her and her colleagues to question if there was something about the detention environment that contributed to the increase in suicides.

“The immediate shock of confinement and disruption to a youth’s regular life can be traumatic and increase the risk for suicidal behavior,” said Ruch. “This might be especially true for incarcerated youth with existing risk factors.”

Suicide is the second-leading cause of death in 10- to 24-year-olds, and more young people in confinement die of suicide than any other reported cause of death, according to the journal article.

An earlier national survey of juvenile correctional facilities from 2000 to 2014 found that suicide rate for youngsters in custody was two to three times higher than for the same group in the general population, wrote the authors.

The numbers were even worse for offenders under age 25 incarcerated in adult facilities. Suicide accounted for 53 percent of all deaths in that age group and population, with rates up to five times higher than those not in custody.

The study also noted that over 75 percent of the young people who killed themselves while in custody did so in the first seven days of incarceration, compared with 50 percent of suicides by incarcerated adults.

And while the authors wrote that previous studies had advocated for ongoing suicide risk assessments for incarcerated youth, the new study found that 93 percent of juvenile facilities screen for suicide intent only at intake. Rescreenings were done only if there was an obvious need.

In addition, the study found that only 44 percent of the facilities conduct screening and assessment with mental health professionals with at least a master’s degree-level education and licensing.

The study also shed some light on the characteristics of the young people who took their lives in custody. Those who died by suicide were most likely to be white, male, and in the 20-to-24-year-old age group. Black young peoples were more likely to kill themselves while in custody — about 23 percent, compared with the almost 11 percent who were not in custody.

Nearly 97 percent of the incarcerated young people took their lives by hanging, strangulation, or suffocation. With general population young people, firearms were the most common method of suicide, at 47 percent.

Only about 23 percent of the in-custody young people left a suicide note, compared with 31 percent of the young people in the general population who killed themselves.