Mischa Barton in trouble ?

Mischa Barton's family are concerned she is heading straight for rehab.The former 'O.C' actress' parents are worried their 21-year-old daughter - who recently collapsed after accidentally mixing antibiotics with alcohol - could follow in the footsteps of some of the troubled stars she has been partying with including Lindsay Lohan, who checked into rehab last week. A source told Britain's Grazia magazine: "Mischa's family is worried she is hanging around with the wrong kind of people because a lot of them are headed to rehab."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."Mischa suffered an adverse reaction to her bronchitis antibiotics and fell ill at a Memorial Day barbecue last month. She was rushed to a Los Angeles medical facility and ordered by doctors to rest.The actress contracted bronchitis after partying at the Cannes Film Festival, where she caused a scene at a lavish bash thrown by jewellers De Grisogono by furiously rowing with model Victoria Silvstedt. In February, Mischa's younger sister Hania, 19, sought help in rehab for an addiction to prescription painkillers.