AMANDA BYNES was placed on involuntary psychiatric hold Monday night, after she started a fire in a woman's driveway in Thousand Oaks, California.
What she's on is called a 5150 hold, and they'll hold her for up to 72 hours while they evaluate her mental condition.
Here's what happened: Someone driving through a Thousand Oaks neighborhood called 911 after witnessing a woman standing in a driveway next to a small fire.
For some reason, Amanda had walked onto the driveway with a gas can and lit the fire. Then she put a flaming rag on top of the gas can. Her pant leg briefly caught on fire, but she wasn't injured.
Several people rushed over to check things out, and Amanda tried to take off in a cab. But by that time, the cops had showed up. They asked Amanda some questions, and determined by her answers that they needed to take her in.
This actually happened in Amanda's old neighborhood, where her parents still live. But the woman who lives in the house had no idea who she was or why she'd want to light a fire in her driveway.
On Sunday, Amanda was kicked out of a retirement community in Thousand Oaks, where she claimed she was trying to visit a relative. Police were called, but Amanda wasn't arrested.
As for why Amanda is back in California, a source says she ran out of money and couldn't find a place to live in New York City.
Meanwhile . . . RadarOnline.com says that Amanda's parents are considering obtaining a conservatorship, just like BRITNEY SPEARS' parents did. And not so coincidentally, Britney's conservatorship was preceded by a 5150 hold.
A source says, quote, "Her parents are absolutely sick with worry about their daughter. They have previously met with lawyers to discuss the possibility of taking legal control of Amanda's life."
For the record, Amanda hasn't been charged with any crimes, so doctors can release her at any time, if they think she's not a danger to herself or others.