Bynes, who turned 28 in April, was diagnosed as schizophrenic and bipolar following an involuntary psychiatric commitment last year.
The commitment follow a string of incidents involving bizarre behavior in public. She reportedly was on the mend earlier this year thanks to her psychiatric stay and a regimen of anti-psychotic drugs.
But Bynes was arrested by a California Highway Patrol officer, after her Mercedes was spotted sitting in the middle of an intersection on Van Nuys Blvd, according to gossip site TMZ.
She was taken in under the suspicion of driving under the influence of drugs or alcohol and police later determined that she was allegedly high on marijuana, according to the gossip site.
Bynes was charged with DUI and released on $15,000 bail. She is still on probation from an earlier DUI conviction.
After a stint in a psych ward, Amanda was released under the custody of her parents, who where appointed as her conservators, with control over her and financial affairs
For a time, there was even talk of her restarting her movie career.
She started as a child star on Nickelodeon and even had her own show. She also stared in the WB sitcom “What I Like About You,” and
She has also had a burgeoning film career that included roles in 2003’s “What a Girl Wants,” “She’s the Man” in 2006, “Hairspray” in 2007 and “Easy A” in 2010.
Her parents’ conservatorship apparently ended earlier this month and Amanda moved into her own Orange County apartment. The tailspin began there, a source said.