SEATTLE (AP) — Rachel Whalen remembers feeling gutted in high school when a former friend would mock her online postings, threaten to unfollow or unfriend her on social media and post inside jokes about her to others online.

The cyberbullying was so distressing that Whalen said she contemplated suicide. Once she got help, she decided to limit her time on social media. It helps to take a break from it for perspective, said Whalen, now a 19-year-old college student in Utah.

There's a rise in cyberbullying nationwide, with three times as many girls reporting being harassed online or by text messa...