Although Bell's palsy is a common finding in the general population, the prevalence of this finding is much greater in these youthful offenders. This suggests an infection of the CNS may be a contributing factor in these school shootings. A common dynamic in perpetrators of the most violent acts is a prior history of both neurological impairment and abuse. Sometimes the neurological injury precedes the abuse, sometimes they begin at the same time, and sometimes the abuse precedes the neurological injury. The presence and interaction of both can contribute to a vicious cycle of increasing social isolation and hostility.
Social isolation is another very major predisposing factor which precedes violence.
Although there are many different explanations most perpetrators have a history of poor social adjustment. On close scrutiny, many offenders do not possess healthy sexual relationships. Another major predisposing factor is substance abuse which can further contribute to the isolation and other issues already discussed. Individuals who feel disempowered, some who feel ineffective and helpless think of violence as a means of acquiring the power, notoriety, or attention they often lack. In adolescents, role models are particularly significant.