(LONDON) -- At age 14 or 15, a perfect storm of surging hormones, immature brains and unfamiliar emotions drive nearly one in 12 teens to deliberately hurt themselves, most often by cutting or burning their own flesh, or by trying to hang, electrocute, drown or suffocate themselves.
"The window of vulnerability for this experience of self-harm appears to open at around puberty," said Dr. Paul Moran, co-author of a study about self-harm published online Wednesday in The Lancet.
Teens, he said, may hurt themselves to block out emotions "they feel to be intolerable." At particular risk, he said, were teens "on a fast-track to adulthood, those kids who are at the margins at school, who are engaged in early sexual activities, who are using alcohol and drugs at a young age."
Families, educators and even self-injuring youngsters may be relieved to hear that in 90 percent of cases, these frightening, aberrant practices resolve on their own, said Dr. Niall Boyce, a psychiatrist and senior editor of The Lancet.
Moran, from the Institute of Psychiatry at King's College London, and co-author Dr. George C. Patton, from the Center for Adolescent Health at the Murdoch Children's Research Institute in Melbourne, Australia, said they believed theirs was the first large study to trace "the natural history" of self-harming behavior from its onset in puberty through young adulthood. They pointed out that self-inflicted deaths, including suicides, rise sharply during that same period.
The study's researchers studied a random group of nearly 2,000 school children, ages 14 and 15, in the Australian state of Victoria, from August 1992 through January 2008. Over the course of those 15 years, and on as many as nine occasions, the students answered questions to assess if, and how often, they'd engaged in self-harm.
Moran said their answers, and the years of observing them, yielded several important insights:
-- Self-harm is common, reported by about 8 percent of 14- to 19-year-olds.
-- At every stage, more girls reported self-harm than boys.
-- Those who cut, burned or otherwise deliberately hurt themselves were more likely to be seriously depressed or anxious, and to report smoking, drinking or abusing drugs. Similarly, a small subgroup of students who began hurting themselves as young adults were more likely to report having been depressed or anxious as teenagers.
-- The proportion of young men and women reporting self-harm substantially declined as they aged.
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