GUYSBOROUGH, N.S. -- A New Brunswick doctor who uses cannabis to treat veterans with PTSD says Lionel Desmond wasn't suicidal and showed no sign he was a threat to others in February 2016, less than a year before the former infantryman killed three members of his family and himself.

"He was very open with his feelings, and he had things to live for," Dr. Paul Smith's told a provincial fatality inquiry, which entered its fifth week of hearings Monday.

"His suicidal thinking had dropped dramatically."

Smith's testimony was considered pivotal to the inquiry because he was the one who signed off on a medical form that allowed Desmond to purchase the semi-automatic rifle he used in the killings on Jan. 3, 2017.

The physician said he was unaware his recommendation would carry so much weight. In fact, he said, he expected Desmond's licence to be rejected by the RCMP or another agency.

"I didn't think I was the final decision maker," he testified.

Desmond, who served in Afghanistan in 2007, was medically released from the army in June 2015, four years after he was diagnosed with post-traumatic stress disorder and major depressive disorder.

On July 2, 2015, he met with Smith, who approved him for treatment using medical marijuana.

"Lionel was a likable guy right from the beginning, " Smith testified. "I didn't have to draw things out of him .... He wore his heart on his sleeve."

However, even though Desmond received psychotherapy and medications while he was in the military, Smith said it was clear he needed more treatment for his PTSD symptoms.

On a scale of 1 to 10, with 10 being the worst, Desmond told Smith the following symptoms rated a 10: hyper-vigilance, depression, flashbacks, anger and feeling disconnected.

Despite those numbers, Desmond rated his suicidal thoughts at 6, and Smith rated Desmond's homicidal ideation at zero.

At the time, Desmond had stopped taking drugs prescribed by military doctors because the pills didn't help with his insomnia, anxiety, depression, lethargy and muscle spasms, Smith said.

Instead, Desmond was smoking about one gram of cannabis daily, which Smith said was the equivalent of two marijuana cigarettes.

Smith prescribed Desmond up to 10 grams of medical marijuana daily, though he described that amount as a ceiling dose. At a follow-up meeting on Oct. 1, 2015, Desmond reported positive results.

"He had a significant improvement in symptoms," Smith said.

But there was a problem a few weeks later, when Desmond's wife Shanna called Smith to tell him her husband was acting aggressively and appeared to be in a manic state.

Smith said Desmond later insisted he was not feeling angry or manic, but he did tell the doctor he was frustrated with his wife for causing financial hardship, and he revealed that the two were headed for a separation.

"The only thing he was stressed out about was money," Smith said. "It's a raw issue. He's pissed off, and he's been that way for years."

The next time Smith met Desmond was on Feb. 23, 2016, when the retired soldier presented the doctor with a medical assessment form from the chief firearms officer in New Brunswick.

The form said Desmond's firearms licence was under review because he had indicated to his wife he was contemplating suicide on Nov. 27, 2015 when he was living in Oromocto, N.B. He was arrested under the province's Mental Health Act and his weapons were confiscated in New Brunswick and Nova Scotia.

Smith said it was his assessment that Desmond was responding well to treatment and wasn't a threat to himself or others.

"Non-suicidal and stable," Smith wrote on the form. "No concerns for firearms usage with appropriate licence."

Inquiry council Shane Russell asked Smith if he was aware of two separate incidents in November 2015, when the RCMP in Nova Scotia were called to deal with Desmond after others complained he was acting in an aggressive manner.

Smith said he wasn't told about those police calls.

"It would have given a slightly different picture," he said. "(But) I thought I wasn't the one to make the final decision."

On Jan. 3, 2017, Desmond bought a SKS 7.62 carbine, which he used later that night to kill his 31-year-old wife, their 10-year-old daughter Aaliyah and his 52-year-old mother Brenda inside the family's home in Upper Big Tracadie, N.S.

He then turned the gun on himself.

This report by The Canadian Press was first published Feb. 24, 2020.

-- By Michael MacDonald in Halifax.