A jury may consider whether cannabis-induced psychosis is a mental disorder that could result in a man who killed his wife being found not guilty of her murder by reason of insanity.
Mr Justice Tony Hunt delivered his charge on Thursday afternoon to the jury in the trial of James Kilroy, who beat, stabbed and strangled his wife Valerie French Kilroy to death at their rural Mayo home.
Mr Justice Hunt told the eight women and four men that psychiatrists had given different opinions on whether Mr Kilroy, a cannabis user, could avail of the "insanity" defence if he was suffering from drug-induced psychosis at the time of the killing.
Dr Ronan Mullaney, a consultant psychiatrist called by the defence, said that Mr Kilroy was suffering from drug-induced psychosis, which he said is a mental disorder under the Criminal Law (Insanity) Act.
As a result of that disorder, Dr Mullaney found that Mr Kilroy did not know that killing his wife was wrong and was unable to refrain from killing her. He said that Mr Kilroy meets the criteria for the "special verdict" of not guilty by reason of insanity.
Professor Harry Kennedy, who was called by the prosecution, said that Mr Kilroy was most likely suffering from cannabis intoxication or withdrawal at the time of the killing.
Professor Kennedy said any mental disorders caused by cannabis use, including withdrawal and psychosis, are consequences of intoxication and are not separate disorders under the Act.
Mr Justice Hunt on Thursday told the jury that the Act is clear that intoxication cannot be used as a defence. Intoxication, he said, is defined as being under the "intoxicating influence" of a drug.
The judge reminded the jury that Professor Kennedy had said drug-induced psychosis falls into the definition of "intoxicating influence". Dr Mullaney, the judge said, believes that interpretation "goes too far" and that intoxication refers only to the direct, acute effects of drug use.
The jury, Mr Justice Hunt said, will have to consider the ordinary meaning of the words "intoxicating influence" in coming to their decision.
Dr Lisa Wootton was also called by the defence and told the jury that Mr Kilroy was most likely suffering from an acute and transient psychotic disorder at the time of the killing.
She also found that he met the criteria for the special verdict.
Mr Justice Hunt told the jury that if they prefer Dr Wootton's evidence, they do not have to consider the definition of intoxication.
Mr Kilroy (51) has pleaded not guilty by reason of insanity to murdering his wife at their home in Kilbree Lower, Westport, Co Mayo, between June 13th and June 14th, 2019.
In her closing speech to the jury, Anne Marie Lawlor SC for the Director of Public Prosecutions, said that the three psychiatrists who gave evidence are "eminently qualified" but "not all experts are equal".
Ms Lawlor said she is not suggesting malafides on the part of Dr Mullaney and Dr Wootton, but she asked the jury whether they can accept their conclusions.
In deciding that Mr Kilroy didn't understand that killing his wife was wrong and that he was unable to refrain from killing her, Ms Lawlor said both had started from the position that everything Mr Kilroy told them about his delusional state of mind was true. "Is that really useful to you in performing your function?"
Ms Lawlor asked. Professor Kennedy, counsel reminded them, told the jury that psychiatrists should not simply presume that what they are told is true.
Ms Lawlor asked the jury if the method employed by Dr Mullaney and Dr Wootton "stands up to scrutiny" and reminded them of certain things Mr Kilroy said to gardaí and psychiatrists that she said show him to be an "unreliable historian".
It was accepted by Dr Wootton that Mr Kilroy said many things that were "bizarre and untrue", Ms Lawlor said, yet the doctor based her findings on things he had said.
Ms Lawlor also reminded the jury that Mr Kilroy told gardaí that while he was killing his wife: "I knew I had fucked up." She asked how that fits with the finding that Mr Kilroy didn't know that what he was doing was wrong.
Ms Lawlor suggested there was evidence of "reverse engineering" in Dr Mullaney's evidence, whereby he started with a conclusion and then found reasons to support it.
Ms Lawlor suggested to the jury that the criteria for a finding of not guilty by reason of insanity have not been met. "For you to find they are, would demand of you to make jumps and leaps that simply aren't there on the evidence.
This is not a case where Mr Kilroy bears no responsibility for what he did."
If the jury finds that Mr Kilroy was suffering from a mental disorder, the question of whether he is guilty of murder or of manslaughter due to diminished responsibility is for the jury to decide, Ms Lawlor concluded.
Patrick Gageby SC, for the defence, told the jury that this is a "very unusual case" where a man with no previous convictions, no history of violence of any sort, who had never come to the adverse attention of gardaí due to domestic violence, had killed his wife in "shocking and revolting circumstances".
Mr Kilroy then put his wife's body into the back of a camper van to the rear of their home, went into his house, jumped out a window and "took to the hills". When gardaí found him some hours later, he was wandering through a field naked and covered in scratches from thorns.
Mr Gageby said the toxicology evidence goes against Professor Kennedy's assertion that Mr Kilroy was intoxicated or suffering withdrawal at the time of the killing. Blood and urine tests for THC - the intoxicating compound in cannabis - were negative, he said.
Mr Gageby said many of the views expressed by Professor Kennedy are incompatible with the science of toxicology.
Mr Gageby accepted that the jury may consider it "a big ask" to return a finding of not guilty by reason of insanity if Mr Kilroy's disorder was induced by cannabis use.
However, if they agree with Dr Wootton that acute and transient psychosis is a better explanation of his behaviour, he said: "That might perhaps lead you more easily than any other route to the question of not guilty by reason of insanity."
Mr Gageby also told the jury that in two other trials, drug-induced psychosis was accepted as a mental disorder. Dr Mullaney, he said, is not "on the fringes" with his conclusion. "It is respectable."
The jury has spent less than one hour considering their verdict and will return today/tomorrow (FRI) to continue their deliberations.
