Bynes' Hollywood career started when she was discovered by Nickelodeon producers Brian Robbins and Dan Schneider.
"It was like a kids comedy camp," Amanda told ET during a set visit in 2001. "They picked like 10 kids out of 30 to do this graduation night and we would do our act -- our comedy act. And then Brian Robbins and Dan Schneider found me there and they asked me if I wanted to audition. It was kind of like [it was] meant to be. It was fate."
After being cast in Nickelodeon's comedy All That and the game show Figure It Out, Bynes eventually got her own live action sketch comedy and variety series -- The Amanda Show -- unprecedented at the time for a 13-year-old. "It's so cool," she told ET at the time. "When I did All That, it's the same crew. It’s like my family here." The show ran four seasons and even spawned another successful Nick series -- Drake & Josh, starring her former castmates Drake Bell, Josh Peck and Nancy Sullivan.
Bynes parlayed early success into young adulthood, starring opposite Jennie Garth from 2002-2006 in the WB sitcom What I Like About You. Though there were rumors the two fought on-set, Garth called Bynes "down-to-earth" in her recent memoir. "It was refreshing to be around her energy," Garth said in Deep Thoughts From a Hollywood Blonde. "She was alive and young and exactly the way she was supposed to be."
And then she tweeted that she was quitting acting -- at the ripe age of 24.
"Being an actress isn't as fun as it may seem," she wrote at the time. "If I don't love something anymore, I stop doing it. I don't love acting anymore, so I've stopped doing it."
A month later, she "unretired" and starred with Emma Stone in 2010's Easy A.
Bynes' legal troubles began in 2012, when she was arrested on suspicion of driving under the influence when she collided with a police car on April 6. Just days later, on April 10, various outlets reported that she was involved in yet another hit-and-run.
But it was her colorful denials on Twitter that raised even more eyebrows.
"Hey @BarackObama," she pleaded to the president. "I don’t drink. Please fire the cop who arrested me. I also don't hit and run. The end."
The California Department of Motor Vehicles eventually revoked her license after she was charged with two misdemeanor counts of hit-and-run, but after even more car drama -- including getting cited with driving with a suspended license and getting her car impounded – questions about her mental health became more and more common as reports of her increasingly troubling behavior began to make headlines.
In the midst of reports that included Bynes locking herself in a dressing room for two hours and getting kicked out of a gymnastics class for crying and talking to herself, her Twitter also began getting more bizarre -- for example, calling out various stars like Jay Z, Rihanna and Zac Efron for being "ugly."
In May 2013, Bynes was arrested for reportedly throwing a glass bong out of her apartment window and smoking marijuana in the building’s lobby, and in July of that year, she was put on a 5150 involuntary psychiatric hold after starting a fire on a random stranger's driveway in Thousand Oaks, Calif.
In August 2013, her parents were granted a temporary conservatorship, and last December, she left rehab after five months in treatment. She seemed to be doing well until recently, when her bizarre behavior started up again.
On October 10, Bynes was admitted to a facility in Pasadena, Calif., and placed on psychiatric hold for a second time. The Bynes' family lawyer Tamar Arminak confirmed to ET this week that her psychiatric hold has been extended for 14 more days.