This article reviews the relationship of violent/homicidal behavior an
d mental illness in both the psychiatric and the nonpsychiatric popula
tion. Violent/homicidal behavior is significantly associated with ment
al illness in all populations studied. It is rather clear that the pre
sence of substance and alcohol abuse and dependence, antisocial person
ality, comorbidity, psychosis, and suicidal behavior are other importa
nt risk factors. Self-rating questionnaires, such as the Homicide Beha
viors Survey (HBS), are also discussed and are helpful in detecting hu
micidal/violent behaviors.