Next April 20 will mark the 10-year anniversary of the day Erik Harris and Dylan Klebold forever altered the definition of school shootings after their rampage at Columbine High School. And how much a culture of bullying at the school, as was alleged as motivators, was a factor may never completely be known. But after three years and $9 million, a new study shows that — not a big shock — healthy relationships between teens and adults reduces the prevalence of peer bullying.