Mischa Barton is back on Instagram after a recent stay in a Los Angeles hospital.

The O.C. alum was allegedly drugged while celebrating her 31st birthday with friends on Wednesday night, and voluntarily admitted herself to Cedars-Sinai Medical Center for treatment in the early hours of Thursday.

In an exclusive statement to PEOPLE on Friday, Barton confirmed that she was released from the hospital — treated for the effects of GHB, a depressant that is commonly placed in alcoholic beverages and is known as a “date rape drug.”

Credit: Pascal Le Segretain/WireImage

She appears to be feeling better, sharing a zen shot of a Buddha statue to Instagram on Monday from California’s Verdugo Mountains.

Police responded to multiple calls about a disturbance coming from Barton’s West Hollywood apartment around 7:15 a.m. on Thursday, PEOPLE confirmed. Upon arriving at her residence, officers found the actress and one house guest. According to authorities, Barton was “fully clothed” and “speaking in coherent statements” before she willingly went to the hospital.

Barton explained the incident to PEOPLE in her own words.

“On the evening of the 25th, I went out with a group of friends to celebrate my birthday. While having drinks, I realized that something was not right as my behavior was becoming erratic and continued to intensify over the next several hours,” Barton said in a statement.

“I voluntarily went to get professional help, and I was informed by their staff that I had been given GHB. After an overnight stay, I am home and doing well,” the statement continued. “I would like to extend a big thanks of gratitude to the professionals at Cedars-Sinai for their great care and professionalism. This is a lesson to all young women out there, be aware of your surroundings.”