Steven Scott, 24, had been released early from a 64-month sentence for attempted murder when he carried out four vicious assaults in five days.
At the High Court in Edinburgh yesterday consultant forensic psychiatrist William Black said Scott was schizophrenic.
Scott of Inchinnan, Renfrewshire, had been heading for a life sentence. As background reports on the danger he might pose to the public were being prepared suspicions arose about his mental health. He was transferred to The State Hospital for assessment.
Scott admitted slashing Ryan Keegan, 19, on March 20 2011, in Kirklandneuk Road, Renfrew, after asking for a light for a cigarette.
Two days later in Renfrew taxi driver Robert Hewitt, 50, got a small cut to his neck when Scott tried to rob him.
Early the next day Scott attacked Stephen O'Hagan as he walked to work in Port Glasgow. Scott also stabbed Steven Maxwell, 23, after asking for a puff of his cigarette. Mr Maxwell suffered a collapsed lung.
Judge Lord Woolman made a compulsion order keeping Scott in the high security hospital and an order meaning he cannot be freed without the approval of the Scottish Ministers.