Amanda Bynes Arrested for DWI in Los Angeles

Amanda Bynes out and about in May 2014 (Splash News)
Amanda Bynes out and about in May 2014 (Splash News)

Amanda Bynes had been doing a good job of lying low in recent months. That all ended over the weekend.

The former child star was arrested at 3 a.m. Sunday for DWI, the California Highway Patrol confirms.

Bynes, 28, has been charged with a misdemeanor after police determined she was "under the influence of an unknown drug," the agency said in a statement.

CHP officers observed Amanda's Mercedes Benz approaching a red light when she stopped in the middle of the intersection. She was then pulled over. Bynes complied with officers, but was unable to complete field sobriety tests.

Amanda was taken to a local station where she was given a drug evaluation and it was determined that she was under the influence of an unknown substance, which impaired her driving. She was then transported to the Van Nuys jail and booked for driving while impaired.

After posting $15,000 bail Amanda was released later Sunday, at 12:44 p.m. She is due in court on Oct. 23, and that's when things could get worse. While the DWI is only a misdemeanor, the Nickelodeon alum was placed on three-year probation in February stemming from her 2012 DUI arrest. She was also told to enter an alcohol-education programs for three months.

There was no immediate comment from Bynes's camp.

The Easy A actress appeared to be on the upswing after a rocky 2013 (in July of last year, she was involuntarily hospitalized after setting a small fire in a stranger's driveway) —  Bynes enrolled in the Fashion Institute of Design & Merchandising in Orange County, California. In the months that followed, she was photographed looking happy and healthy, even enjoying a birthday getaway to Mexico with family and friends.

Amid reports of mental illness, her lawyer shot down rumors in April that she was suffering from schizophrenia.

"There has been much speculation about Amanda's medical condition," attorney Tamar Arminak told Yahoo. "She has remained silent because she believed it was best to keep her mental health diagnosis private. However, she asked me to dispel certain rumors."

Arminak continued:  "Amanda does not have schizophrenia, nor has she ever been diagnosed with it.” She added at the time the Hairspray actress "is currently is on zero medication. She's devoted to living her life as healthy as possible. She's never had a history of abusing alcohol or hard drugs, and she's proud to say she's been marijuana-free for the past nine months."