The woman was out walking with two medical orderlies and a guard at around 5pm on Monday in the Gothenburg suburb of Västra Frölunda.
When the group turned a corner onto Svängrumsgatan the woman made a dash for it.
She ran straight at a five-year-old boy playing on his bike in the vicinity and pushed him onto the ground. She then kicked him in the face.
The woman was quickly restrained by her caregivers.
“If you hadn’t stopped me I would have beaten him to death,” the Expressen newspaper reports her having said.
Anders Oxelbrand with the Frölunda police confirmed that the boy had been taken to hospital with face wounds.
“This was really ugly, this could have ended in disaster,” Oxelbrand told Expressen.
The woman was arrested and taken in by police for questioning on Monday evening. She is being detained on suspicion of attempted murder.