The incidence of suicide in nearly all age groups has increased by 24 percent since 1999—and by 200 percent among girls between the ages of 10 and 14. Theories behind such astounding unprecedented increases, reported recently by the Centers for Disease Control and Prevention, vary. Some research says that among older Americans, the recent recession may have played a part, though the correlation is not a simple one. As for why so many more young girls are killing themselves, the answers there, too, are complicated. Girls between the ages of 10 and 14 showed the greatest rise in suicide of any age group since 1999, from 0.5 per 100,000 to 1.5 per 100,000 in 2014, according to last month’s CDC report.