The former child star started posting on the social media site from her @amandabynes account, reported People magazine.
Bynes, 28, aimed insults at her family's lawyer, Tamar Arminak as well as her father and controversial celebrity manager Sam Lutfi in addition to posting nonsensical musings.
She also defended her mental state, telling followers she has headed to court.
"I am going to court today with my lawyer to prove that I am more than capable of handling my personal life and finances and I am enraged," she posted on Twitter.