It's all a gimmick similar to what Joaquin Phoenix did.
According to THR, before the meltdown, this was what Amanda Bynes said:
In a profile last year, THR reported Bynes' downward spiral began as she became more frustrated with her career – which frequently saw her cast in family friendly films such as What a Girl Wants (2003), She's the Man (2006) and Sydney White (2007).
"Everybody had her as a goody-goody. She couldn't break out of that genre," a high-level agency source told THR last year. "Her frustration was, 'I could have played this role; I could have played that role. I'm not getting the Lindsay Lohan roles.'”