The 29-year-old defendant, who was born four years before his mother, Mette-Marit, married Norway’s Crown Prince Haakon, is not a member of the royal family or a public figure.
During his first appearance in court on Tuesday, he was seen shaking. He is understood have had hospital treatment overnight.
Høiby was arrested on Sunday on suspicion of assault and wielding a knife and remanded in custody for four weeks. However, he did not return to custody before his statement on Wednesday.
He took a seat in court and after several minutes in which he looked overcome by the occasion, he regained his composure and told the court he had had a lot of sex, drugs and alcohol because he had an extreme need of validation.
“I am known for being Mamma’s son. Nothing else,” he told the three judges.
“Few can relate to the life I have led. A lot of parties, alcohol, some drugs.”
His trial coincides with a tense moment for his mother, who was found to have exchanged hundreds of messages with the late US sex offender Jeffrey Epstein over a three-year period.
The royal palace said on Wednesday that Crown Princess Mette-Marit had postponed a private trip “until further notice”, without giving further details.
She has expressed regret and poor judgement over the correspondence.
However, the storm of criticism over the unguarded, warm tone of the exchanges has heaped pressure on the royal house, when Mette-Marit is also seeing her son on trial for rape.