The health board’s investigation found staff had noticed “bizarre” behaviour during her shifts, including locking herself in a room on a ward.
She also locked doors in corridors that were not allowed to be locked in case of fire or if staff were needed to help deal with violent patients.
Adeleiyi, who had no training in restraint techniques, had access to confidential patient notes and made additions to observation notes herself.
The court heard health bosses said the potential risks “could have been catastrophic”.
Adeleiyi used the ID of a registered healthcare support worker who fled from the UK to Nigeria using a false passport.
Judge Recorder Mark Powell KC told Adeleiyi: “You put the patients at risk… you put staff at risk.”
Adeleiyi was ordered to carry out 100 hours of unpaid community service.