The Dublin youth appeared again at the Dublin Children's Court today.
In September, the 17-year-old boy pleaded guilty to harassing BBC News Northern Ireland's Aileen Moynagh between October 2020 and February last year.
The boy, who has a range of complex disorders, cannot be identified because he is a minor.
The court heard he stalked her online after developing an "obsessive crush".
The teen had been previously cautioned about similar trolling of two RTE journalists and had an "unhealthy interest" in women journalists.
Detective Garda Ken McGreevy said the boy, then aged 16, was behind a litany of unsolicited and unwanted communications to the BBC journalist. He sent them via email, Twitter, Facebook and LinkedIn.
Despite being warned by gardai not to contact her, he travelled to Belfast and was a couple of hundred yards from her workplace.
Out of fear, she moved out of her house for five days and was concerned about her movements.
Last month, the young internet troll entered another guilty plea to a threat to harm another journalist, who was not named during the proceedings.
He made the threat on November 9 last to a Garda and two other people during a meeting at a youth justice project.
The teenager confessed to previously hiding in bushes on the grounds of RTE in Dublin. He watched the journalist as she drove from her workplace car park.
Detective Garda Michael McCallion said the boy threatened that he had wanted to disfigure her.
He also admitted he wanted her "off the air".
Judge Paul Kelly described a psychiatric report as "quite alarming reading". It stated the boy showed no remorse; he was at high risk of re-offending, violence and continued stalking. In addition, the report noted the boy was a "disabled, isolated, lonely and sometimes and angry young man" and presented "unique challenges".
The report also said that medication had been recommended, which might lessen the risk.
A Probation Service assessment stated the teen had expressed awareness of the impact of his offence, but it also concurred that he was at high risk of re-offending.
The judge noted that Tusla, the child and family agency, has now a "considerable plan of supports".
Judge Kelly described Ms Moynagh's victim impact statement as "harrowing", and he praised the generosity and compassion she showed during the proceedings. He also noted the heartache of the boy's father, who had told the court he had spent years trying to get specialist help.
He imposed a six-month sentence for the harassment offence. But he deferred activating the order pending a case review on July 27.
He warned the boy that he must attend recommended mental health services and therapeutic interventions, engage in education but he was not allowed unsupervised internet access.
In relation to the threat to the second journalist, who did not provide a victim impact statement, he ordered the teenager to remain under the supervision of the Probation Service for the next 12 months.
The boy, accompanied to court by his father, remained silent during the proceedings and nodded to indicate he understood the order.
Defence solicitor Eoghan O'Sullivan told the court the boy's frustrated family had been trying to get him help since he was eight.
He said the HSE identified an appropriate facility, however, budget issues prevented it from being available.
Earlier, the teen's father vented his frustration at the lack of help for his son. He described the developments as a "self-fulfilling prophecy".
Ms Moynagh reported the harassment first to the PSNI, but the complaint was not passed on to the Republic, and the journalist later contacted the gardai.
The "high functioning" boy, who wants to be a journalist, had been barred from Twitter 150 times under various aliases.
In December, she delivered a moving victim impact statement in court and said she hoped the case would "shine a light" on the dangers of social media and act as a deterrent.
"I felt I was constantly looking over my shoulder, suspecting every male I walked past or saw in the local shop. And the trolling continued," she said. However, she also told the youth, "I don't wish you any ill; I just want you to stop."
Concerns were raised earlier that the boy had also been sending unwanted messages to a female student in Galway.
He also caused a person to lose their job after he made a baseless allegation, the court was told.
The teen had a breakdown and was hospitalised for two months after similar harassment of two RTE journalists, which did not result in a court prosecution.
The court heard there had been diagnoses of autism, Asperger's syndrome, Attention Deficit Hyperactivity Disorder, Oppositional Defiant Disorder, Tourette Syndrome, Obsessive-Compulsive Disorder, and Trichotillomania hair-pulling disorder.