A 32-year-old Co Kilkenny man who bludgeoned his mother to death later told gardaí that "demons took over".
Niall Stapleton admits killing Siobhan Stapleton at Glebe Lodge, Kilfane, Thomastown, on May 25, last year but denies the charge of murder, by reason of insanity.
Earlier, his sister Sinead fought back tears on the stand as she described finding her injured mother.
The jury heard that Niall Stapleton used the handle of a garden fork to repeatedly strike his mother over the head.
Initially he told gardaí that he had seen a man fleeing from the house, but later he confessed that something in himself had snapped.
He said demons took over and that it was all a blur. He told detectives: "I can’t believe I’d do something like that - if I did I should be in prison for life".
The 32-year-old had been diagnosed with paranoid schizophrenia and was off his medication at the time of the attack.
He has no prior history of violence.
The court heard he has been at the Central Mental Hospital since his arrest last year.