A new study comes to the unsettling conclusion that 21 percent of high school girls have been subjected to physical or sexual abuse by someone they have dated, double what researchers had previously believed.

In addition, 10 percent of high school boys report some form of physical or sexual assault from someone they dated, which is consistent with previous surveys, according to a report published by the Centers for Disease Control and Prevention in the journal JAMA Pediatrics, as reported by USA Today. The results were based on a survey of 13,000 high school students.

Teens who are victims of violence are twice as likely to consider suicide. In addition, boys who have been abused by a dating partner are four times as likely to have been bullied online, whereas girls are twice as likely, according to the report.

The study suggests that abuse can turn the teens into violent people themselves, with the results indicating that boys and girls who have been the victim of violence more likely to carry a weapon, get into fights, and engage in substance abuse. They also are more likely to be more promiscuous than their peers.

However, correlation does not imply causation, so researchers can’t be sure that such abuse at the hands of someone they are dating is causing such behavior. After all, people who are already depressed and contemplating suicide could be more likely to be drawn into abusive relationships.

Teens who are abused don’t have it happen just once, typically. The study found that teens usually reported being assaulted more than once.

It’s a tough thing for parents to deal with, as often teens try to hide this abuse from them. Since abusers often isolate their victims, the teens may not have anyone else to turn to either. Sometimes, a doctor is the only person a teen will talk to about the situation, as long as parents aren’t in the room, according to the USA Today report.