A consultant psychiatrist has told a court it is his view that a Cavan man who smothered another patient in a psychiatric unit was insane from drug withdrawal symptoms.

Ian Harman (50) of Carrigallen Mountain Lodge, Cootehill, admits causing the death of Michael Traynor (82) at Cavan General Hospital in June 2011, but denies murder.

The jury has heard Mr. Harman smothered a patient with dementia in the psychiatric unit on the morning of June 27th 2011.

He later said he wanted to kill someone so he would be locked up forever.

He had spent the days before the alleged murder pacing the hospital yard for hours at a time, and later told consultant psychiatrist Dr. Bob Johnson that it was like torture - his thoughts went to places they had never been before.

Dr. Johnson, who is a defence witness, believes Ian Harman was legally insane and could not stop himself from killing Michael Traenor due to severe withdrawal symptoms from the anti-psychotic drug Olanzapine.

He will be cross-examined by the prosecution this afternoon.