Amanda Bynes' parents are deeply concerned that their daughter may hurt herself or others unless they are allowed to assume control over her medical care and finances, court filings show.
The petition Richard and Lynn Bynes filed on Friday not only details her public incidents of disturbing behaviour, including several arrests, but also reveals that the former child star has stated fears that she is being watched by smoke detectors and devices in the dashboard of her car.
Ventura County Superior Court Judge Glen M. Reiser delayed ruling on the conservatorship petition, stating that there was no rush to act because the actress is under a two-week psychiatric hold at a hospital.
Reiser scheduled a hearing on the issue for August 9 and said he also wants to meet one-on-one with Bynes before making a decision.
"We are deeply concerned that Amanda poses a substantial risk to herself, to others, and to property based on recent events in her life," the filing from Bynes' parents states.
It cites numerous instances of increasingly bizarre behaviour by their 27-year-old daughter in the past year.
Bynes was put under the psychiatric hold on Monday after authorities said she set a fire on the driveway of a home in the Los Angeles suburb of Thousand Oaks, where she grew up.
Her parents learned she had returned to California from New York City two days before the incident. Their daughter told them she "cabbed it" but they say they do not know how she actually travelled cross-country or where she has been staying.
"We believe she is essentially homeless," the filing states.
Before moving to New York, Bynes "was extremely paranoid about being 'watched'", the filing states. "She would cover smoke alarms with towels, tape windows shut, and cover her car's dashboard with cardboard and tape out of fear that cameras were watching her from inside these places."
Bynes, who was 13 when she landed her own hit TV show, The Amanda Show on the Nickelodeon cable network, went on to star in the TV series What I Like About You and several movies, including Hairspray and She's the Man.
Her last film credit was 2010's Easy A, which starred Emma Stone.
Bynes amassed $US4 million ($A4.35 million) in savings but has spent $A1.2 million in a short amount of time, her parents' petition states.
They state they suspect some of the money has been spent on drugs and plastic surgery, citing bills they have received from doctors and large payments their daughter has made to people they don't know.
"Amanda has profound issues with her body image and is obsessed with the idea that she (and others) are 'ugly'" the petition states.
"She talks incessantly about cosmetic surgeries that she wants to have completed.
"We are concerned that the surgeries she wants to have are dangerous and detrimental to her health," the filing states.