Kyle James Swannie, of Hoofields, Lerwick, pleaded guilty to acting in a threatening and abusive manner during phone calls to the social workers where he told them he knew where they lived – and told one he would “slit your throat”.
The court heard how Swannie had made the two calls on 18th October last year.
Defence agent Tommy Allan said there was “no justification” for the abuse, which included shouting and swearing.
He added: “These threats cannot be accepted or condoned.”
Procurator fiscal Duncan MacKenzie described how one of the victims had taken the threat so seriously she stayed in a hotel overnight until police had Swannie in custody.
Mr Allan said his client, who has been diagnosed with ADHD, apologised three times via text and in person and was looking to attend an anger management programme.
He also stated Swannie suffered from depression and is unable to work, adding that, in this case, “there was a little bit more to it than meets the eye”.
Sentencing was deferred until 2nd February for a background report.