Amanda Bynes is a danger to herself and others, according to police officers who detained her over the weekend ... which means she's back on a 5150 psychiatric hold.
Our law enforcement sources tell us Amanda is the one who called LAPD Saturday morning to report a woman in distress.
TMZ broke the story ... Amanda was intercepted by LAPD officers and taken to a police station for a medical evaluation to determine if she needed further treatment.
As it turns out, it was determined Amanda needed to be brought in on a mandatory psychiatric hold -- she can be held for up to 72 hours, by law.
It's the latest stumble in the former Nickelodeon star's downward spiral ... and it's the second time this year she's been placed on a psych hold. The first instance happened in March, when she was found naked, roaming the streets of downtown Los Angeles.
Amanda was released from a mental health facility only 2 months ago, but we had heard from people close to her that she was isolated and not doing so well.
Now, she at least has an opportunity to get treatment.