. Between 1977 and 1986, more than 300 parents were killed each year by their own children.

Why Kids Kill Parents

Tragedy in the family: When kids murder their parents.

By Kathleen M. Heide, published on September 01, 1992 - last reviewed on October 01, 2009

EXCERPT
By far, the severely abused child is the most frequently encountered type of offender. According to Paul Mones, a Los Angeles attorney who specializes in defending adolescent parricide offenders, more than 90 percent have been abused by their parents. In-depth portraits of such youths have frequently shown that they killed because they could no longer tolerate conditions at home. These children were psychologically abused by one or both parents and often suffered physical, sexual, and verbal abuse as well--and witnessed it given to others in the household. They did not typically have histories of severe mental illness or of serious and extensive delinquent behavior. They were not criminally sophisticated. For them, the killings represented an act of desperation--the only way out of a family situation they could no longer endure

http://www.psychologytoday.com/articles/200910/why-kids-kill-parents