When Edward Mason fired his gun at Germain Gaulin last April, he was experiencing alcohol-induced hallucinations, Yukon Supreme Court heard Tuesday.

Mason, 64, believed that Gaulin, 43, with whom he was drinking in a cabin near Watson Lake, was rushing toward him with a knife yelling, 'I'll carve you an asshole!' according to Vancouver-based psychiatrist Dr. Shabehram Lohrasbe.

At the time of the murder, Mason was both seeing and hearing things that did not exist, the court heard.

The second witness to take the stand in the trial, which began Monday, Lohrasbe said Mason was experiencing an episode of psychosis brought on by heavy drinking and advancing alcoholism. The clinical name is alcohol-induced psychotic disorder.

'(Mason's) mental functioning was grossly abnormal at that time,' Lohrasbe said of the moments when Gaulin was shot.

He disagreed with the conclusion of Dr. Todd Tomita's diagnosis, which the court heard Monday.

Tomita found no grounds for psychosis in his interview with Mason. He said his actions were the result of disorganized thinking caused by alcohol. As a result, Mason would not qualify for section 16 of the Criminal Code of Canada defence of mental disorder.

Mason was in fact suffering from psychosis due to his advancing stages of alcoholism, according to Lohrasbe's report.

While there is no widely accepted definition of psychosis, Lohrasbe explained one diagnosis is symptom-based and tracks certain kinds of hallucinations over time.

The night of Gaulin's murder was not the first time Mason experienced hallucinations. He had heard voices from time to time, including those of his deceased father and friend Jim. Jim had given him instructions on how to fix a propane tank.

Mason had heard these voices when he was sober, as well as when he was drunk. That suggests his hallucinations stemmed from more than simply consuming alcohol, Lohrasbe said.

Also, extreme and abrupt actions that result from a reaction to alcohol usually occur in new drinkers or non-drinkers. Mason was an alcoholic.

'Simple intoxication is hard to accept for such bizarre behaviour,' Lohrasbe said. 'It can't be viewed as a simple alcohol pathology.'

Another key incident involving hallucinations occurred in 1995. Mason was also drinking heavily on that occasion and pulled out a knife, stabbing a man. He was convicted for this crime in 1996.

Just as he hallucinated that Gaulin was rushing toward him with a knife, when in fact he wasn't, Mason also believed that the men he was drinking with at that time had set him up to rob him. This was not, in fact, the case.

'He has no doubt that that's what happened.... He believes he was set up and acted in self-defence,' Lohrasbe said. 'He believes he had no choice in the matter.'

The inability to decipher between real memories and reconstructed memories is a sign of psychosis, according to Lohrasbe.

Crown prosecutor David McWhinnie pressed him to explain why he concluded that Mason was mistaking hallucinations. Lohrasbe said it's not possible to say definitively whether Mason knows the difference between memory and reconstruction.

That does not, however, change Lohrasbe's diagnosis that Mason suffers from psychosis as a result of alcohol.

Mason's inability to remember also complicates both the diagnosis and the case. He has no recollection of the murder, nor of mutilating the body. He also has difficulty remembering his previous hallucinations and parts of his life.

This is a common symptom of advancing alcoholism, Lohrasbe said.

Lohrasbe reported that during the interview when Mason was asked to differentiate between real memories and those he had created, he could not.

'I can't do that because there are things I remember clearly, like in a movie, but I've been told they couldn't have happened,' Mason is reported to have said.

This was an example of where hallucinations may have been mistaken for real memories, Lohrasbe said.

As with Tomita, Lohrasbe found Mason to be co-operative and seemingly honest.

'He was polite, pleasant and co-operative during the interview,' he said. 'He seems to be an open and honest individual... a concrete, no-nonsense kind of guy.'

He described Mason, who has sat very still throughout both days of trial, as an intelligent man who reads the paper and watches TV every day in prison.

A long-standing alcoholic, Mason resigned himself to that life after he lost his wife and children, he said.

When Mason spoke about Gaulin, it was with sadness.

'When he spoke about the victim, it was in a sad, regretful, remorseful way,' Lohrasbe said.

Lohrasbe also described Mason as a sad person.

'He's quite indifferent to his fate,' he said. 'He's a sad guy who's sitting there waiting for things to play out. He's very indifferent to what happens to him.'

The lawyers presented their closing arguments today to Deputy Justice Rene Foisy, visiting from Alberta. He was scheduled to render his decision at 3:00 this afternoon.

There is no jury.