An autistic man beat his mother to death because he couldn't cope with the stress of moving home, the Central Criminal Court has heard.
Bijan Afshar (23), has pleaded not guilty by reason of insanity to the murder of his mother Lynn Cassidy at her home in Deepdales, Bray, Co Wicklow, on June 26 or 27, 2014.
Consultant forensic psychiatrist Dr Brenda Wright told defence counsel that she believed Mr Afshar had no control over his actions when he lashed out.
She said he was so distressed at the prospect of moving home that he believed his only options were to convince his mother to stop the sale or kill himself.
When she told him she couldn't prevent the house being sold he "lost control" she said. "At the time he was unable to refrain from committing the act because of his mental disorder."
The defence told the jury that under the Criminal Law (Insanity) Act, a person cannot be guilty of murder if they were unable to control their actions due to a mental disorder.
Dr Wright said that Mr Afshar's autism was effected by his parents' separation in 2008.
After performing poorly in his Junior Cert exams he refused to go back to school and became obsessed with computer games. He refused to shower and would wear the same clothes for days or even weeks.
He became violent on one occasion when his parents redecorated his room without his permission.
His condition deteriorated further when he learned that he would soon be moving out of the house he had shared with his father and brother for most of his teenage and adult life.
The house had been sold as a result of his parents' separation and they were due to move out the day after Mr Afshar fatally attacked his mother.
Dr Wright said the prospect of the move caused Mr Afshar great distress.
She said this kind of response is often seen in people with an autistic disorder as they have unreasonable reactions to any change in routine or loss of control over their environment.
On the night his mother died Mr Afshar went to her house to tell her the move was causing him great anxiety and that he was feeling suicidal.
He became frustrated when he felt that his mother was not taking him seriously, or didn't believe him when he said he was thinking of killing himself.
He said her responses seemed "robotic and pre-programmed". His feelings were hurt.
She said his "poor emotional regulation" as a result of his disorder caused him to lose control.
Dr Ronan Mullaney of the Central Mental Hospital appeared for the prosecution.
He said that he agreed with Dr Wright's conclusion.
The trial continues.