Former OC actress Mischa Barton may be joining fellow former child model Lindsay Lohan and her BFF Nicole Richie with an upcoming trip to rehab.

M.B’s parentals are worried that their twenty-one year-old daughter – who recently collapsed after accidentally mixing antibiotics with alcohol – could have substance abuse issues.

“Mischa’s family is worried she is hanging around with the wrong kind of people because a lot of them are headed to rehab,” a tattle tells the British tabs.

“Mischa doesn’t really hang out with her old friends the way she used to and the people she’s been spending time with – Lindsay, Paris and Nicole – have them totally freaked out.”

“The last thing her family wants is for her to turn into some Hollywood party girl.”

In February, Mischa’s younger sister Hania, 19, sought help in rehab for an addiction to prescription painkillers.