There has been limited success in reducing bullying in K-12 schools, according to a recent study.

Researchers from the University of California-Los Angeles found that although schools are trying different approaches to protect students, efforts to curtail bullying are often disappointing. They believe this has to do with a lack of substantial commitment and resources.

"Band-Aid solutions, such as holding one assembly a year that discourages bullying, do not work," Jaana Juvonen, a UCLA professor of psychology and lead author of the review, said in a statement. "We are trying to figure out the right balance between comprehensive programs that are costly and require a lot of staff training versus programs that require fewer school resources."

For the study, researchers analyzed more than 140 studies - a mix of long-term and "snapshot" research - that were conducted in the U.S., Australia, Finland, Norway, Sweden and the United Kingdom.

Using this data, researchers also debunked some common misconceptions about bullying. For example, while it was previously assumed that verbal aggression and exclusion were bullying tactics used more commonly by girls than by boys; researchers found that boys use the tactics as much as girls do.

Their findings also showed that gay and lesbian students and students who are overweight tend to get bullied significantly more than other students.

"Starting in elementary school, kids with characteristics that make them stand out are much more likely to get bullied," Juvonen said. "They are prime targets for bullies because they are more likely to be friendless, and when they have nobody to defend them, the bullying often escalates."

She added that children with social connections - even one friend - are less at risk of suffering severe symptoms after being bullied.

Researchers noticed some schools have been successful combatting bullying by training bystanders to respond to bullying. However, Juvonen said the training needs to be a school-wide initiative that provides students with strategies against bullying and unites them in the cause.

The findings were published in the journal Annual Review of Psychology.