A man who stabbed his mother to death with a kitchen knife has been committed to the care of the Central Mental Hospital in Dundrum, Dublin.

Paul Henry, who stabbed, punched and kicked his 47-year-old mother, Ann Henry, before her death at The Spinney, Abbeytown, Roscommon Town, on 17 September 2011, was found not guilty of murder by a jury last week by reason of insanity.

At a sentencing hearing at the Central Criminal Court, sitting in Castlebar in Co Mayo today, Dr Damian Mohan, consultant forensic psychiatrist at the CMH, furnished a report on the 28-year-old for Mr Justice Paul Carney.

Dr Mohan said that Henry had been detained at the Castlebar Mental Health Unit between 27 July 2011 and 11 August 2011.

He said he had been discharged against medical advice by a Mental Health Tribunal.

Just over a month after his release, Henry killed his mother in an attack inside and outside her home.

Dr Mohan said Henry had killed his mother because he believed she was "conspiring against him" and wanted to kill him.

The witness said he had assessed Henry on 2 May as suffering from a mental disorder characterised by a delusion or false belief system that his mother wanted to kill him.

Dr Mohan said that if Henry was to be discharged there would be an increased risk of him harming himself or others.

Therefore it was appropriate that he be detained in conditions of therapeutic security such as exists at the Central Mental Hospital.

"There is a bed available for him today", Dr Mohan informed Mr. Justice Carney.

The court heard that Henry will be assessed at the hospital on a six-monthly basis.