A University of British Columbia student who attempted to kill a classmate in 2016 has returned to his native Saudi Arabia after being discharged from a forensic psychiatric hospital.

Thamer Hameed Almestadi was 18 when he attacked Mary Hare, a student who lived in his dormitory, in October 2016.

Accused of slitting Hare's throat and attempting to choke her, he was charged with attempted murder, aggravated assault and assault with a weapon. Two years after the attack, a judge said he was likely suffering from a brief psychotic episode and he was found not criminally responsible.

In an interview conducted just hours after the violent attack, Almestadi told police that he'd believed God commanded him to sacrifice her.

During his trial, the court heard he told a police sergeant that he thought she was the devil, and that he'd been overwhelmed by schoolwork and lack of sleep that day.

Following the verdict, Almestadi was held at a forensic psychiatric hospital in Port Coquitlam, but last month it was decided that he would be released.

A decision from the British Columbia Review Board said the now 20-year-old started having delusional thoughts about two weeks before the attack. He went to Hare's dorm room "in an acutely psychotic state" and began stabbing her neck with a knife when she opened the door.

He was subdued by other residents who came to investigate the source of Hare's screams. Upon arrest, he said he felt remorseful.

The report said he'd experienced previous events as a test from God, and that the theme of sacrifice in a religious recording he'd previously been listening to played a role in his behaviour.

"In Dr. Smith's opinion, the only motive for the attack was his psychosis. Lack of motivational clarity is not, in our experience, an unusual phenomenon."

The doctor, who produced a psychiatric assessment at the request of Almestadi's lawyers, suggested his psychosis cleared in November, and said she believed there was a low risk of future violence.

Two other doctors agreed with Smith's diagnosis and, following a later assessment, said Almestadi has been co-operative and polite during his time in hospital.

The doctors told the review board he is now high functioning, and his psychosis is in remission without the help of medication. The report before the BCRB said he has expressed further remorse and is considered reasonable.

"These factors, including the brevity of the episode, are positive signs that he may not relapse," the BCRB report said.

However, the report said that if there was a future episode, it could involve violence.

Further assessment of the risk is linked to the possibility of another episode, the report said, and he has no additional history of violence, violent attitudes or ideas, anti-social behaviours or anger issues.

"There is no evidence of any animus toward women," the report said.

The report presented to the BCRB said his risk of relapse has declined to less than 50 per cent over time, as more than a year has passed symptom-free, including during his time in the "highly stressful and alien environment of a pre-trial centre."

The report added that there were signs of his deteriorating condition before the attack on Hare, and that, if he were in an environment where anti-social behaviour would be noticed, a future relapse could be prevented.

The report suggested that environment would be his parents' home. Both parents have been living in B.C. since the assault to help their son deal with legal problems, and have visited him regularly and been involved with his treatment.

His family has also identified a psychiatrist he could work with in Saudi Arabia, and Almestadi has already been accepted as a patient. The doctor hopes to work with Almestadi and his parents to educate them on treatment and warning signs.

The family has agreed to take Almestadi to hospital if needed, and monitor his medication intake if ever prescribed.

Because of his immigration status, an exclusion order required Almestadi be deported under Canada Border Service Agency escort to Saudi Arabia if discharged from the hospital.

While one member of the board dissented to the discharge, highlighting the brutal nature of the attack and that the motive is unknown.

"The only explanation for the psychotic episode is that Mr. Almestadi succumbed to the stresses of everyday life – stresses that can be anticipated in the future," board member Paula Cayley said.

"The evidence available to the Board, is that on the single occasion Mr. Almestadi experienced a psychotic episode he attempted to sacrifice a virtual stranger for reasons that remain largely unknown, other than he was experiencing stress."

Several other concerns were raised, including that one doctor said Almestadi had been guarded at times since arriving at the hospital, and that Cayley felt the assessment period should be extended.

Ultimately, the majority of the panel found he did not present a significant risk to public safety and discharged him.