05/31/2007 AT 01:00 PM EDT
Patti Davis, the daughter of Nancy and Ronald Reagan, has some advice for Lindsay Lohan
: Take rehab seriously.
"It makes me angry when I see how the opportunity of being in rehab can be abused as nothing more than a slick PR move. A brief retreat from the paparazzi," writes the 54-year-old former first daughter in a first-person commentary
"How lucky these celebrities are to be able to go to one of these facilities (which are not cheap) and to benefit from the wisdom and help that waits behind the gates."
Regarding her own experience, "I struggled for years to learn on my own what someone like Lohan could learn in months, if she were willing to do so. Of course, that learning also has to be followed by practice. Every day. Forever. But it can start in rehab," Davis writes.
"I never went to rehab. I should have. I plunged willingly, desperately, into addiction at the pliable age of 15."
She says her drug of choice "was speed... pretty colored tablets called amphetamines."
Davis – who had been long estranged from her parents before reconciling before her father died in 2004 – says her life was hell "well into my 20s. Cocaine replaced pills at some point. But that wasn't a big change."
Ultimately, she says, "I quit because I decided not to die. I quit all alone – the same way I started. I quit in spite of long nights when the taste of cocaine would come up in my throat – drifting up out of my cells, I guess – and I wanted it so badly my nails dug into my palms until they drew blood. I quit by trying to live inside a body that was so much older than my years."
Davis warns, not only Lohan but others ("Fellow bad girl Britney Spears wasn't in [rehab] long enough for her hair to grow back. Meanwhile, Paris Hilton zipped right by rehab and picked up the GO DIRECTLY TO JAIL card," Davis writes): "Abusing ourselves with any kind of substance abuse is a violation of the gift of life – it isn't what any of us were put here for. And treating rehab like it's just a strategic career move is practically blasphemous."