Troubled actress Lindsay Lohan took to her Twitter page last night to admit failing recent drug tests. She also admitted to being a substance abuser and she swore she is going to do better.

But past history (and the fact that she initially denied failing her drug tests) tells us that we can’t believe her.

The star-struck UCLA drug rehab doctors who “treated” Lindsay for substance abuse incorrectly recommended an early rehearse for her because she told them what they wanted to hear.

Though the docs failed in their duty to protect Lindsay from herself (and the public from her), they did get one thing right: they diagnosed Lindsay with a personality disorder.

Because of her diagnosis — complicated by her non-compliance and drug abuse — we can’t believe one word Lindsay says, or Tweets.

Like I wrote yesterday, this story will end when Lindsay Lohan kills herself or someone else.