Lindsay Lohan has been released from a rehabilitation centre just 22 days into a court-ordered three-month programme.

The early discharge came after media reports that doctors treating the actress didn't believe she was suffering from drug or psychiatric problems that were previously diagnosed.

Celebrity news website Radaronline.com said the actress was escorted out of the Los Angeles hospital unit's back door into a waiting limousine on Tuesday afternoon, while TMZ.com said Lohan was to receive outpatient care from now on.

A court hearing was scheduled to take place today, but Lohan was not expected to attend.

Lohan was released early from jail earlier this month after serving 13 days of a 90-day sentence for violating her probation on a 2007 drunk driving and cocaine possession charge. She was released on the grounds of good behaviour and also to help alleviate overcrowding.

She immediately entered a residential rehab programme in Los Angeles for a 90-day stint ordered by the court as part of her sentence.

But the prosecutor in her case said two weeks ago that health care professionals were likely to recommend an early release for Lohan, with follow-up treatment as an outpatient.

TMZ.com has reported that doctors believe Lohan was wrongly diagnosed with attention deficit hyperactivity disorder, for which she has been taking medication for several years.

TMZ said she was also incorrectly diagnosed more recently with bipolar disorder.

Lohan admitted in 2007 that she was addicted to alcohol and drugs, and went to rehab three times. She was ordered to wear an alcohol monitoring anklet in May this year and was jailed for missing multiple alcohol education classes imposed as part of her probation three years ago.

The career of the once promising actress, who starred in Mean Girls and The Parent Trap, has foundered in the past three years, with Lohan hitting the headlines repeatedly for nights on the town and bizarre behaviour.

Her mother Dina has blamed a "hardball" judge for over-reacting and sending Lohan to jail. She has also said her daughter plans to return to New York from Hollywood once she leaves rehab.

Lohan's legal troubles have delayed shooting on her next movie in which she will play 1970s porn star Linda Lovelace. Lohan was last in movie theatres with the 2007 flop I Know Who Killed Me.

- NZ Herald staff