Former Lindsay Friend 'She's a Lost Cause'

4/26/2010 9:00 AM PDT

Former Lindsay Lohan Friend -- 'She's a Lost Cause'

One of Lindsay Lohan's former close friends tells TMZ virtually all of her friends have just thrown in the towel.

The ex-pal, who requested anonymity but we know was very close to Lindsay, says, "talking to Lindsay is like talking to a wall -- and if you ever say anything negative to her, she cuts you off."  The friend described her as "a lost cause."

As for getting Lindsay help, the friend says several of Lindsay's buddies have tried reaching out to her mother, Dina -- but mama is in denial.