Depression: As many as 8% of adolescents in the U.S. are believed to suffer from clinical levels of depression. Although the presentation of depression varies among individuals, typical presentations reflect depressed mood, fatigue, feelings of hopelessness and helplessness, irritability, negativity, and thoughts of suicide. Adolescents suffering from depression are at an increased risk for illness, as well as for interpersonal and psychosocial difficulties including substance abuse which have been found to be associated with violence in the schools. These risks may increase further among adolescent boys, when the depression is accompanied by a conduct disorder and alcohol or other substance abuse. Fava and Rosenbaum (1999) reported that as many as one in three individuals suffering from depression demonstrate anger attacks or acute outbursts of anger in response to emotional stress.

Suicide is among the leading causes of adolescent deaths. Among youth who develop major depressive disorder, as many as 7% may commit suicide in their young adult years. A review of the school violence literature indicates that roughly one out of seven school shooters commit suicide. Not surprisingly, many of the risk factors associated with school violence also are risk factors for suicide, including stress, the death of a parent or loved one, the break-up of a romantic relationship, and abuse or neglect. Research demonstrates that adolescents who have experienced depression for more than two years are at the greatest risk for committing suicide, making suicidal ideation a salient warning sign and strong predictor of chronic depression and possible aggression against oneself or others. Many of the school shooters identified in the literature demonstrated characteristics of depression prior to their violent actions.

Aggression: Antisocial and behavioral disorders in general, as defined in the DSM-IV commonly include psychological traits such as an affinity for violence, thoughts or actual behaviors of hurting people or animals, poor anger management skills, a history of destructive behaviors, and a confrontational interpersonal style. Nationally, one third of teen-aged youth report that they have been involved in a physical altercation in the previous year, with males reporting a higher incidence (40.5%) in comparison to females (25.1%). Threat assessment among potential school shooters may help to identify students presenting with aggressive traits typically marked by malevolence and acts of violence, vandalism or property damage, and hurting others or animals. Additionally, uncontrolled anger and expressions of violence in writing or artwork were found to be indicative of aggressive behaviors.

Alienation: Adolescence marks a change in the function and importance of the peer group. During this time, youth begin to rely less on their family unit and rely more on their peers to discuss problems, feelings, and fears. Alienation of students by classmates can dramatically impact their coping resources. Alienation can take the form of peer rejection and/or bullying. Peer rejection refers to the rejection that unpopular and socially isolated students are subjected to by their peers at school. Peer victimization, also known as bullying, refers to repeated, unprovoked, harmful physical or psychological actions by one or more individuals against another. Bullying includes hitting, kicking, pushing, intimidating, name calling, teasing, taunting, and making threats. Bullying may also include exclusion and rejection of an individual from a group. Peer rejection is associated with risk for violent behavior and depression, both of which contribute to further alienation . The literature indicates that school shooters commonly harbored feelings of rejection, isolation, and loneliness, and felt that they did not belong or fit in. For these individuals, aggression may actually have been a means to attain social status, as aggression has been characterized as an important status consideration among adolescent boys 

Egocentricism: O’Toole (2000) identified egocentrism as common among school shooters. Typically, these students displayed a lack of empathy, an exaggerated sense of entitlement, an attitude of superiority, an exaggerated or pathological need for attention, and the manipulation of other people. In a similar study, the American Psychological Association (1999) identified the persistent lack of empathy as a warning sign for potential violent behavior.  

If not alienated, school shooters identified in the literature tended to be affiliated with a club, clique, gang, or other students with similar beliefs;  many had a history of drug use. However, very few of the school shooters identified in the literature were taking any drugs, prescription or illicit, at the time of their attacks. It is not uncommon for others to have known about the shooters’ intentions and, in some cases, to have actually provided encouragement. This finding supports the notion that aggressive youth tend to gravitate toward one another. Inconsistent and inequitable disciplinary practices and poor administrative support also have been shown to accelerate patterns of aggressive and violent behavior among students which is particularly problematic as these youth already tend to lack a sense of positive involvement in the school community . These factors, as well as those previously discussed, in combination with the typical student code of silence and poor school security, have contributed to the incidents of fatal school violence, particularly in the absence of thorough threat assessment procedures.

Coping:  Maladaptive coping strategies (e.g., denial, behavioral and mental disengagement, alcohol and drug use) have been linked to personality and mental health problems, such as poor social adjustment and depression. Most of the perpetrating students identified in the school violence literature were reported to have presented with a history of frustration, criticism, disappointment, failure, rejection, or humiliation marked by inappropriate, exaggerated, immature, and disproportionate problem-solving strategies, poor locus of control and a lack of anger-management skills.

Stress: Research suggests that the effects of stress may be cumulative and may account for a significant percentage of the various behaviors that are commonly attributed to mental health problems. Research demonstrates a strong association among adolescent self-reported stressful life events and the degree of psychological and behavioral functioning. Poor resilience in response to negative or stressful life experiences is often implicated in the development of behavioral and/or psychological disorders (e.g., depression). The development of these conditions, in turn, may become the source of further stress. Victimization is particularly stressful and has been shown to increase the risk of violent behaviors among at risk youth. Victimization can take the form of physical or sexual abuse, as well as lesser forms such as maltreatment from a bully or victimization by peers in the form of either a physical assault and/or emotional abuse. The American Psychological Association (1993) noted that victimization may result in mental health problems including academic dysfunction, hostility, depression, and suicidal ideation. A history of victimization by a bully, in particular, has been shown to be strongly associated with targeted acts of school violence.