The aggravated assault sentencing hearing for Vakhtang Makhniashvili has been adjourned until Thursday after several disruptions and delays.

At one point on Tuesday, Makhniashvili, 51, stood up in the prisoner's box and told the judge he'd like to dismiss his lawyer.

The native of the Republic of Georgia claimed to have suffered seven months of sleep deprivation, to pleading guilty under pressure and to having been given drugs without consent.

The defendant was first thrust into the public eye when Mariam disappeared without a trace from outside her high school.

The judge adjourned the hearing and ordered the man to speak with his lawyer, which caused a 20-minute delay.

Justice Rebecca Rutherford remained concerned about whether the 51-year-old defendant understood the charges against him and the implications of pleading guilty.

A forensic psychiatrist told the court on Tuesday that he believes Makhniashvili to suffer from a mental illness. However, more time is required to precisely determine what the defendant is suffering from, the doctor said.

As a result, sentencing will take place at some future point. However, Makhniashvili will be back in court Thursday.

It's been almost two years since Mariam vanished from her North Toronto neighbourhood.

The 17-year-old and her brother George had arrived in Toronto from Georgia to reunite with their parents just weeks before her disappearance.

Despite an exhaustive search, Toronto police have never been able to locate Mariam or find an explanation for her disappearance.

Meanwhile, Makhniashvili pleaded guilty in May to three counts of aggravated assault.

His charges stem from the stabbing of a former neighbour in May 2010 and the November stabbings of David and Delores Langer, a couple previously unknown to the Makhniashvilis who had stepped forward to post bail for the previous attack.

Vakhtang Makhniashvili told court in May he stabbed his 26-year-old neighbour in May 2010 after accusing him of being responsible for his daughter's disappearance.

Unidentified remains had been found in a northeast Toronto park that day. They turned out to be those of a man.

Makhniashvili also said he stabbed the Langers outside their home after blaming them for an unfavourable newspaper article about his family. He turned himself in at a police station

Last November -- George, the last to see Mariam before her disappearance -- vanished briefly after a squabble with his parents. He turned up unharmed at a police station in Vaughan the next morning.

With a report from CTV Toronto's Austin Delaney