Characteristics of Bullies
Researchers Berthold and Hoover (2000) noted that bullies are more likely to have cheated on tests, have limited adult supervision at home, have brought weapons to school, and have experimented with drugs, alcohol, and cigarettes.  They also report that 19.8% of students admitted to bullying others at school.  Of these students, males were twice as likely as females to be the perpetrator.

In another study, Bosworth, Espelage, and Simon (1999) discovered that boys engaged in bullying behavior more frequently than girls do.  They learned that many students (81%) reported at least one act of bullying, but only 7.7% reported frequent acts of bullying.  Their study determined that there are no significant relationships between bullying and grade level, ethnicity, and family type.  They did find, however, that students with a recent history of misconduct as well as students who had access to guns have a higher incidence of bullying behaviors.  This study pointed out that other common characteristics among bullies include high levels of impulsiveness, depression, and anger. Finally, the researchers found that students who have limited nonviolent conflict resolution skills were more likely to engage in bullying behavior. 

In addition, Finnish researchers report that bullies are at risk for depression and suicide (Kaltiala-Heino, Rimpelä, Marttunen, Rimpelä, and Rantanen, 1999).  Engaging in aggressive behavior can lead to loneliness, depression, and poor peer acceptance (Crick and Grotpeter, 1995).  Girls tend to be lonelier than boys, and boys tend to be more depressed than girls (Crick and Grotpeter, 1995). 

Reasons Why Bullies Bully
One possible root of bullying could stem from witnessing domestic violence.  DeVoe and Smith (2002) learned that survivors of domestic violence worry that their children will imitate the abuse they witnessed.  Another study showed that the less involved parents are with their child, the more likely the child will exhibit bullying behavior (Flouri & Buchanan, 2003).  

British researchers propose that preschool-aged children with an insecure attachment to their peers may be more aggressive than their classmates with secure attachment to peers (Monks, Smith, and Swettenham, 2005).

Emergence of the Bully/Victim
Haynie, Nansel, Eitel, et al (2001) determined that 7.4% of students report bullying another student at least once over the last year.  Interestingly, 53% of the bullies reported being victims, too.  This unique group of students is known as bully/victims.  Because so many bullies are also victims, it creates a gray area.  Bullies and victims can no longer be seen as opposite ends of a continuum.  The study done by Haynie, et al. (2001) can only attest to the existence of the bully/victim; more research needs to be done on the etiology of the bully/victim.  Duncan (1999b) found that the majority of bully/victims were on the giving and receiving end of sibling bullying.  Duncan also points out that bully/victims were more likely to suffer from higher levels of anxiety, low self-esteem, pessimism, fatigue, and loneliness than other children were.