This follows Kuznetsov’s frequent quarrels with other patients who accused him of demonic practices.
The incident reportedly occurred at night and hospital staff had to interfere to stop the fight.
Kuznetsov, who declared himself a prophet and established a cult of Orthodox believers, is held responsible for persuading its members to barricade themselves in a cave in the Penza Region.
Around 30 doomsday believers including, four children, have spent more than three months underground.
They are waiting for the end of the world, which they believe will come in May.