The barrister for a Dublin man, who strangled his ex-girlfriend in a city hotel, has said that the totality of the evidence supported his client having a mental disorder.

However, the prosecutor said the accused "well knew" that what he was doing was wrong, was well able to control himself and that there could not be any question of diminished responsibility due to such a disorder.

The barristers were giving their closing speeches today in the Central Criminal Court trial of Eric Locke, 35, who used a fake Facebook profile to meet Sonia Blount after she had cut contact with him.

Remy Farrell SC, prosecuting, described consultant psychiatrist Dr Seán Ó Domhnaill as "the cornerstone of the defence for diminished responsibility".

He noted that the other defence psychiatrist said he was relying on Dr Ó Domhnaill's diagnosis of Pervasive Developmental Disorder in Mr Locke.

"Dr Ó Domhnaill is wholly unreliable," he said. "His lack of familiarly with the evidence is simply stunning."

Mr Farrell suggested that there must be a basic concern for his competence as a witness in such a case.

"He has come to a series of outlandish conclusions that not even the defence are prepared to rely on," he continued. "He says this is actually a case of insanity."

Mr Farrell said nobody else was "buying that".

The barrister said the defence had asked its psychiatrists to proceed on the presumption that Mr Locke's account of what happened in the room was true.

Mr Locke said he had brought items to restrain her so she would listen to him. He said she screamed when she saw them and that he panicked and strangled her.

"This is the foundation of this defence," he said. "If something totally different, substantially more sinister, more deliberate happened in that room, then your deliberations may be very, very swift indeed."

He told the jury that the accused had thought through every step of his plan to meet her in the hotel room. He pointed to messages in which, posing as Shane Cully, he was "needling her" to leave a keycard for him at reception.

"He has anticipated there very well may be a peephole in the door. He doesn't want to run the risk of knocking on the door, and Sonia Blount looking out to see who it was," he said. "You can be damn sure that if Sonia Blount had looked out that door and seen Eric Locke, she would not have opened that door."

He said the evidence clearly showed that Eric Locke knew well that what he was doing was wrong, was well able to control himself and that there could not be any question of diminished responsibility.

"This is a man, who until the eve of a murder trial, did not have any psychiatric diagnosis. That should set off alarm bells to you," he said. "I suggest this construct of diminished responsibility is little more than that."

Patrick Gageby SC, defending, said that the three psychiatrists, who had given evidence, were "markedly different".

"It is not their function to decide the question of whether Eric Locke is truthful," he told the jury. "You're entitled to cherry pick."

He said that Dr Ó Domhnaill had appeared poorly prepared and not very good at court presentation, but said he did appear to have expertise in developmental issues. He said he had not heard any evidence to the contrary, and was "not so sure" that he was challenged on his diagnosis of PDD.

Mr Gageby said that the question of PDD stood up.

"Eric Locke has always been different since his teens," he said.

"When they broke up, he went to pieces," he continued. "He gave up his job."

He outlined his suicide attempt and consequent treatment in hospital.

"What do these things say about his mental condition?" he asked.

"The totality of the evidence supports a mental disorder," he said. "We're not asking that you absolve him of responsibility; it's a question of diminishing it substantially."

He told the jurors that this was for their consideration, not for one of the doctors.

"It's not the function of psychiatrists to put a benign spin on one side or the other. They should stay out of the facts," he said. "My respectful position to you is that there is, on the balance of probabilities, cause to find diminished responsibility.

Mr Justice Michael Moriarty will charge the jury on Monday.