HOW COULD YOU STAB YOUR OWN MOTHER?

Assuming the police accusations are correct, how could a son violently attack his mother like that, leaving her dead with stab wounds to her head and face?  Elaine Walsh, 55, was found dead in her East Memphis home early Saturday morning April 21,2012 . Her 22-year-old son, William Walsh, has been charged with first-degree murder in her death. The confrontation started about 1 a.m. Saturday at the Walsh family home in the 5400 block of Gwynne, according to police.About that time, Elaine Walsh went to speak with her son about about noise he was making in the house.
John Walsh, her husband, told police he went to bed, assuming she would join him after talking to their son. However, she never returned. Sometime between 5:30 and 6 a.m., William Walsh came into his parents' bedroom and, according to the police affidavit, told his father that he had done "something terrible" and that he had "killed someone." John Walsh then walked out into the living room and found his wife, dead on the sofa. How could you kill your mother? The woman who gave you life, the woman who raised you and nurtured you.