It's hard work keeping up with Lindsay Lohan – as girlfriend Samantha Ronson is apparently finding out to her cost.

The celebrity DJ – who has been on a more or less constant timetable of gigging and partying in recent months – is said to have suffered a "scare" brought on by exhaustion and stress.

Doctors were called on Sunday after Sam had made a series of frantic phone calls and it was decided she should be hospitalised..

"She was calling around. She knew she had done something wrong," the 'friend' of Sam's tells Life & Style.

"She's been suffering from depression and from lack of food and sleep. Gal pal Lindsay Lohan has been helping her through this as she has been through it herself two years ago."

A rep for Lindsay declined to comment on the claims.

See Sam and Lindsay together in less stressful times below