Teenager sectioned after hitting sister in head with hammer
The 16-year-old, who was believed to be suffering from psychosis and hearing voices in his head, will now be treated for his problems following the brutal attack.
But a judge was persuaded by medics that it was not necessary to impose a restriction order which put more controls over his eventual release.
Colin Meeke, prosecuting, told Swindon Crown Court how the attack happened last summer after the family had been out celebrating his mum's birthday.
They had been for a meal in Marlborough before returning to their village home where the parents went to bed, leaving their son and 14-year-old daughter downstairs.
He was on the computer and she was watching TV before the boy went to the kitchen, got a hammer, went behind her and attacked her.
The court was told she was later found to have seven 'curved linear lacerations' from where she had been struck by the tool.
She also suffered a broken hand when she put it up to try and prevent the blows landing on her from above.
"She, in great distress, went to get help from her parents for assistance. He left the house on his bicycle and cycled the relatively short distance to Marlborough," Mr Meeke said.
He stopped someone outside the Green Dragon and told them to call the police as he had 'done something terrible' and attacked his sister.
When he was questioned he gave quite a full account of how things had been building up and he launched the attack.
"He was terribly remorseful and regretful about the injuries he had caused his sister," Mr Meeke said.
The boy, who cannot be named for legal reasons, pleaded guilty to wounding with intent to cause grievous bodily harm.
James Tucker, defending, asked the court to impose a hospital order but urged the judge not to impose a restriction order.
And psychiatrist Dr Simon Hill, who is treating the teenager, backed up the request saying it could be detrimental to his recovery.
He said it would make it more difficult for the lad to have home visits and also for family therapy to take place.
The medic said "He has committed a very serious offence but I think he is abnormal in the amount of insight he has in to it and how compliant and engaged he is with mental health services. I think he in unusual in that."
He added "It is remarkable that all the psychotic symptoms have gone so quickly. About one third of young people who have a psychotic episode don't have another."
And also told the judge "At the moment I don't think he presents a risk to anyone, bearing in mind his mental state."
Imposing a hospital order Recorder Michael Vere-Hodge QC said "I think I am persuaded a restriction order is not necessary.