The Care Quality Commission (CQC) found staff at Deneside Court in Jarrow were not adequately skilled and medicines were not administered properly.
The commission said its management of "challenging" patient behaviour "was not safe".
The home has been approached for comment.
The 40-bed facility, which cares for adults with learning, physical and neurological disabilities, had "not sufficiently improved to protect people", the CQC said.
Head of adult social care in the region, Ros Sanderson, said staff were not always properly trained to meet the specific needs of residents with diabetes and learning and mental health difficulties.
Some staff reported not feeling safe and inspectors found staff and residents "were not protected from potential harm".
"Some of the care staff told us they were frightened by the behaviour of some of the people who used the service and this led to them not attempting to de-escalate behaviour and thus leaving situations to deteriorate to the point the police needed to be called," the report said.
The home relied on temporary agency staff but failed to check they had the required skills, it said.
Risk assessments were not made and reviewed correctly and necessary improvements not always acted upon.
"This is not good enough," Ms Sanderson said.
Inspectors were "so concerned with the medicines management" at the home they returned to look specifically into the pharmacy.
They found some emergency medicines not available and others being given past their use by date.
The CQC decision can be challenged.
A care home is in special measures after being rated inadequate following concerns reported by police and care professionals.