If bullying were a disease, it would be an epidemic in schools.
National statistics from 2010 -- the latest available -- show more than a quarter of all kids have experienced bullying, and that more than 30% experience bullying once a month.
Nationwide, 13 million kids will be bullied this year, according to the Bully Project, which was formed in the wake of a 2009 suicide of an 11-year-old in Georgia.
Three million children -- 160,000 every day -- miss school because they're afraid of being bullied, according to the U.S. Department of Education.
Bullying seems a precursor for criminal behavior, especially for the bullies. National statistics show that boys identified as bullies in grades six through nine had one criminal conviction by age 24, and 40% had three or more arrests by age 30.
Anecdotally, a story close to home may show that a bullying victim acted out in a violent manner. On April 5, 1984, the same day that Steve Carlson is alleged to have killed Tina Faelz, a former friend testified that Carlson was bullied himself, tossed into a dumpster at Foothill High School after a confrontation with members of the football team.
Both bullies and their victims show an increased risk of suicide, according to national and international studies.
Bullied teens are at an increased risk of suicide, now being called "peer-abuse driven bullycide." Victims of bullying are between 2 to 9 times more likely to consider suicide than non-victims, according to Yale University studies; a study in Britain found that at least half of suicides among young people are related to bullying. At least one international study indicated that bullying victims can carry those scars into adulthood, where they can show up as symptoms of post-traumatic stress disorder.
Even being a witness to bullying can be harmful, making the witness feel helpless, or that she or he could be the next target.
Six out of 10 kids witness some form of bullying at least once a day, according to the American Society for Prevention of Cruelty to Children (ASPCC) and at least one study shows that students who watch their peers get bullied could become as upset, if not more so, than the victims themselves. That's according to a report in the December 2009 issue of School Psychology Quarterly, which is published by the American Psychological Association.
Students who watched bullying -- name-calling, kicking, hitting, spreading rumors and threats of violence -- were more likely to report "greater psychological distress" than bullies or their victims, according to the study, which surveyed 2,002 students ages 12 to 16 at 14 public schools in England. That study also shows that bullies and bystanders may also be more likely to take drugs and drink alcohol.
Beyond that, bullying is illegal. California is one of 46 states with anti-bullying laws.
It's also among the 41 states that have created anti-bullying policies for schools. In 2011, AB 9 -- known as "Seth's Law" -- was signed by Gov. Jerry Brown. That law requires every school in California to have anti-harassment and anti-discrimination policies and programs in place.
The law, which went into effect July 1, 2012, is named after 13-year-old Seth Walsh who, because of bullying, committed suicide in 2010.
Under AB 9, schools must take complaints about bullying more seriously. The law requires schools to include in their complaint procedures and methods for receiving and investigating discrimination and harassment complaints.
Schools are now required to act on discrimination and harassment complaints so that investigation and resolution may be reached quickly, and faculty and staff at schools are required to intervene when they witness acts of bullying.
California law has also cracked down on cyberbullying, using social media and other electronic methods to harass, taunt or embarrass others. School officials can suspend or recommend expulsion for students who engage in harassment using electronic devices, whether it's done on or off school grounds.