Similarly, there may be implied covenants of good faith and fair dealing which can be invoked by employees against the employer, the doctrine of respondeat superior imposes agency obligations on the employer, and OSHA standards require that an employer do what is necessary to protect the life, safety, and health of employees. Finally, the criminal justice system has a number of remedies that may be applied to potential assailants including laws against threatening, hate crimes, stalking, brandishing a weapon, and trespass. At times obtaining a restraining order is an alternative that a potential victim or that victim's employer should consider. Workplace violence is a complex phenomenon which requires an examination of both the assailant, the victim, and the setting in which the assault takes place. What causes some individuals to become violent is not well understood.
Biological theories describe neurochemical linkage to violent behavior.
In particular, studies show that low levels of the neurotransmitter serotonin or its bi-products is a powerful predictor of future excessive aggression. Sociocultural theories explore the substrate of violence in the conditions of the community from which the individual comes. While mental illness is often associated with violence, only a minority of persons with mental disorders are actually violent and most violent offenders are not suffering from mental illness. When individuals do become violent due to a mental illness, they are usually more easily recognized by their bizarre or unusual behavior and may have a documented history of treatment or hospitalization. The more problematic cases are those where individuals have personality disorders which are not mental illnesses but maladaptive patterns of thinking and behaving.