An 18-year-old Cape Breton man convicted in the brutal murder of his girlfriend is considered a high risk to violently reoffend, according to a psychologist testifying at the teenager's sentencing hearing.

In August, the teenager was found guilty of second-degree murder after stabbing his 17-year-old girlfriend more than a 100 times. He was 16 years old at the time of the murder, which happened in Whitney Pier in December 2010.

The teenager said he took pills and drank moonshine at the time of the murder.

The man's name and the victim's name are shielded by a publication ban under the Youth Criminal Justice Act.

The hearing, which began Monday, will be used to determine whether the teenager should be sentenced as a youth or as an adult. The Crown is pushing for an adult sentence.

Debra Jellicoe, a psychologist with the IWK Health Centre who specializes in risk assessment of aggressive youth, testified on Tuesday and said she spent 20 hours with the man over seven days to assess him.

Jellicoe said the teenager told her the murder had ruined his life and he's still in disbelief that he killed his girlfriend.

She testified the teen shows remorse for the murder but little remorse for other violent acts he's committed before and since the incident.

Rehabilitation is 'questionable'

The teenager was using illegal substances as recently as this month while at the provincial youth facility where he's being held, court heard.

Earlier testimony in the sentencing hearing detailed how the man has also been in two fights while in custody. During one fight, he had to be stopped from stomping on another inmate's head.

The man has had several convictions as a youth, including assault with a weapon.

Jellicoe said that long history of violent behaviour concerns her, as does the man's anti-social behavior, violent outbursts and substance abuse.

Based on her assessment, Jellicoe told the court the teen is at a high risk to violently reoffend.

"It is questionable whether he could be rehabilitated under the youth sentence," she said.

There were also positive aspects in Jellicoe's assessment. She said the teen wants to go back to school and be involved in activities while in the youth facility.

Victim impact statements are expected to be read on Wednesday. The defense is expected to call witnesses later this week.