Supreme Court Justice Lex Lasry​ on Friday said Brian Browning had murdered his wife of 21 years when in a rage "in an all too familiar incident of domestic violence".

A jury in May found Browning guilty of murder after rejecting his claims that taking Restavit sleeping tablets, which contained the sedative doxylamine, made him psychotic when he repeatedly stabbed his wife Cath, 47.

Browning, 54, claimed he had been hallucinating throughout the night after taking at least six sleeping tablets before using a kitchen knife to repeatedly stab his wife at Skye about 6am on December 19, 2013.

After the stabbing, Browning threw the bloodied knife on to the floor and said: "Bitch."

Mrs Browning was killed nine days after telling her husband she wanted to end their marriage. The couple had both been having issues with drinking and gambling coupled with financial problems.

Justice Lasry said Browning had never been violent towards his wife before waking and killing her and given the murder was so out of character, the most likely explanation was the "pressure-cooker effect".

He pointed to psychiatrist Lester Walton, a key witness during Browning's trial, saying Browning had possibly been suffering from the "pressure-cooker effect" when he killed his wife.

"Sometimes you'll find people who are passive by nature, not given to violence or using angry words, they can soak up conflict and criticism and difficulties, cumulating over years, and then finally the pressure cooker explodes, if you like, they can't contain it any longer," Dr Walton told the jury.

Dr Walton, who interviewed Browning on April 30, 2014, said the father of two had been unhappy, was in a degree of emotional turmoil, somewhat depressed, and not sleeping before the murder after being told his marriage was over, but was not suffering from a drug-induced psychosis.

Dr Walton said he had never in his experience come across a case of doxylamine-induced psychosis.

Justice Lasry said despite the "pressure-cooker" effect on Browning, the community expected domestic violence to be denounced in the strongest terms by the courts and jailed the baker for 18 years with a non-parole period of 14 years.

Defence barrister George Georgiou, SC, had previously told the court Browning's daughters, Amy, 21, and Rhiannon, 19, continued to support their father and regularly visited him in jail after he brutally killed their mother.

Mr Georgiou urged Justice Lasry to take into account Browning's daughters' decision to maintain a close relationship with their father, despite having been very close to their mother, when it came to deciding what sentence to impose on him.

Justice Lasry said the daughters' support of their father was to their credit and he was willing to accept Browning regretted what he had done but his level of remorse was not significant.