The defence lawyer for a man accused of fatally stabbing a high school student and seriously wounding another says he will likely pursue "a defence of not criminally responsible as a result of mental disorder" when the case goes to trial in the fall.

A B.C. Supreme Court judge ruled Thursday that Gabriel Klein's trial will start on Oct. 7.

The B.C. Review board announced Klein was fit to stand trial earlier this month after he was found unfit in April, and again in September when the board heard he'd been diagnosed with schizophrenia and had been hearing voices.

"He had voices in his head screaming at him all the time, 24 hours a day. It's very hard to concentrate on a conversation, let alone evidence in court when it's further dialogue going on in your head," Martin Peters told CTV News after Thursday's hearing.

Klein was charged with second-degree murder and aggravated assault after the fatal stabbing of 13-year-old Letisha Reimer and an attack on another girl at Abbotsford Secondary School in November 2016.

The board heard on Jan. 15 from the accused's lawyer and psychiatrist, Andrew Kolchak, that his mental state had improved significantly.

Klein, who once appeared in court shirtless and covered in a blanket, looked far different during Thursday's hearing.

He was heavier than in the photos that have circulated of him and had longer, curly hair. Most noticeably, he seemed more alert than in any of his other court appearances.

"He had a change in his medication and it's a miracle. It's really turned him around," Peters said.

The judge decided Klein will remain in a psychiatric hospital until the trial is over in November.

With files from CTV Vancouver's Breanna Karstens-Smith