New York, July 14 (IANS) Troubled actress Lindsay Lohan has turned to self-help books for advice as she prepares to serve time behind bars.

The 24-year-old star, who has to surrender to authorities till July 20 following a 90-day jail sentence stemming from the violation of her 2007 probation terms, was spotted carrying author Susan Shapiro Barash’s book ‘Toxic Friends: The Antidote for Women Stuck in Complicated Friendships’.

‘A friend recommended the book to Lindsay to help her get through the these tough times, and for her to appreciate who her real friends are,’ people.com quoted a source as saying.

The book helps people ‘figure out which (friends) you should keep and which ones you should rid yourself of’, added the source.

Lohan is focused on improving her quality of life – particularly her social circle.

‘Lindsay’s cleansing herself of all the toxic influences in her life,’ said the source.

Lohan was sentenced for violating the terms of her probation stemming from a 2007 DUI (Driving Under Influence) arrest last week. She will also be spending another three months in rehab.