Dr. Daniel J. Flannery at Case Western Reserve University in Cleveland and colleagues said they conducted a thorough examination of past studies focusing primarily on targeted and rampage, or spree, shootings.
Targeted shootings are those where there is a specific target, individual group or institution. Rampage or spree shootings are those that involve multiple victims, either known or unknown to the assailant.
The study found there were some characteristics shared by past shooters -- narcissism, depression, low self esteem and a fascination with violence -- but there were not enough similarities to develop any distinctive profile of another potential shooter.
"School shootings are not all the same and may require different approaches to prevention and treatment, especially with respect to identifying risk factors at the individual, school or community levels,and particularly with regard to examining the role that mental health issues may play to increase risk for perpetration," the study authors wrote.
The findings are scheduled to be published in the January issue of Current Psychiatry Reports.
However, a study last year by Michigan State University's Hyunkag Cho and colleagues on the risk factors of the 2007 Virginia Tech shootings by a 23-year-old student that left 33 dead.
Cho said many of the risk factors were essentially universal to mass U.S. shootings including access to guns, media exposure to gun violence and that males are much more likely than females to perceive violence as a legitimate way to resolve conflicts.
Cho said more attention should be given to prevention efforts. Among the study's recommendations: more education for parents, teachers and school officials about the early signs of distorted gender images and misconceptions about mental health needs.