Lindsay Lohan is not addicted to prescription drugs.

The 'Mean Girls' actress - whose father Michael has repeatedly insisted she has a problem with legal substances - has amazed doctors at the UCLA Medical Center with her responses to treatment, leading them to recommend she only stay in the facility for a maximum of 30 days, rather than the 90 days she was ordered to spend there by a court.

A source told X17online: "Lindsay may have taken prescription medication, but she doesn't have 'an addiction'.

"She's been through detox, but had no withdrawal symptoms, so doctors don't believe her issues were as serious as they were led to believe initially."

In addition, the insider - who also revealed the actress' former girlfriend Samantha Ronson visits her "four or five times a week" - says the 24-year-old star has been misdiagnosed with psychological problems, claiming Lindsay's troubles stem from the difficult relationship her parents Dina and Michael have with one another.

The source added: "The only thing Lindsay suffers from is having two narcissistic parents and she fills the void by hooking up with destructive people and bad habits.

"Her mom Dina bad-talked Michael for so long that Lindsay and all her siblings ended up disliking him but she needed something to fill the father void, so she started acting out."

A court hearing has been scheduled for August 25 to discuss whether Lindsay should be released from rehab early.

The troubled star was sentenced to 90 days in prison and a 90-day rehab stint for breaching the terms of her probation set for a 2007 driving under the influence (DUI) conviction.

She was released from jail after serving just 13 days on her sentence.