Lindsay Lohan's drug and alcohol use is escalating out of control - and experts warn she's killing herself!

The troubled actress is snorting massive amounts of cocaine mixed with Ecstasy, taking downers to sleep and boozing daily, insiders say - and pals fear she has a death wish.

"Lindsay's drugging and drinking is out of control! She learned nothing in rehab," a friend of the 20-year-old actress told The ENQUIRER.

"Her friends are afraid she has a death wish."

Lindsay's substance abuse kicked into high gear when she hit the Coachella music festival in Indio, Calif., in late April.

Pick up this week's ENQUIRER for all the details!