Mohammed Abbkr was found guilty of attempting to murder two elderly men in separate incidents as they walked home, one from a mosque in London in February and another in Birmingham, central England, in March.
The CPS said there was no evidence Abbkr, 29, was motivated by a particular ideology, so the incidents were not treated as a terrorist attack.
Abbkr was sentenced at Birmingham Crown Court to a hospital order, which means he cannot be released without the approval of British government ministers. He requires treatment for what the sentencing judge described as "a severe mental illness".
"These were horrific acts of violence against two elderly members of the public," said Nick Price, head of the CPS Special Crime and Counter Terrorism Division.
"Mohammed Abbkr's actions resulted in severe injuries and psychological trauma to his victims and caused considerable shock and concern to the communities in London and Birmingham," Price said.
(Reporting by Sam Tobin; Editing by Sachin Ravikumar)
