Lindsay Lohan is being treated for an addiction to email.

The 'Machete' actress - who voluntarily entered into a substance abuse program at the Betty Ford Clinic in Los Angeles late last month - has reportedly had her phone usage cut, with staff also urging her to reduce the amount of time she spends on social networking websites.

A source told the New York Post newspaper: "Lindsay is only allowed to use her phone for two hours a day, and only to keep in touch with family and close friends.

"Before, she would repeatedly and compulsively email her friends if she was ever in a situation where she felt lonely, and she would vent on twitter."

The policy has been implemented so Lindsay can "concentrate on herself" during therapy.

Lindsay is due in court on October 22 for a probation hearing, after she failed two drugs tests last month.

The 'Mean Girls' actress - who served 13 days of a 90-day jail term behind bars in July - returned to prison following the failed tests, but ended up spending just a matter of hours behind bars after posting $300,000 bail.

Though the next hearing could see her jailed again for violating the terms of her probation for a 2007 driving under the influence (DUI) conviction, Lindsay's friends don't believe the prospect of going back to prison worries the star.

One pal said: "The fact is jail doesn't scare Lindsay. Before she did her time earlier this summer, she was petrified. Having spent time behind bars, it doesn't have that effect on her. Jail isn't a deterrent for her, period."