03/28/2014 AT 02:00 PM EDT
Mackenzie Phillips breezes into the Pasadena Recovery Center through the staff entrance, settles into a chair at the front of the room and prepares to lead a counseling session for 30 or so addicts.
A few minutes in, a meth addict who was admitted to the center only a few days earlier insists he's ready to go home.
"Mack," as Phillips is known to her clients, looks him in the eye and urges him to avoid the "overconfidence" that can accompany early recovery.
"You're just a young guy who's got his whole life ahead of him," she says forcefully. "I'm a 54-year-old woman who wishes she had this guidance when I was 21. God knows what a difference that would have made."
It's a role reversal the former sitcom star – who detailed her lifelong struggle with drug abuse in her blistering 2009 memoir High on Arrival – often dreamed about during her four-decade battle with addiction.