The lawyer, Robert Gottlieb, tells TMZ, "There is no question that what happened this week, as well as the other [arrests] were all drug-related ... She is not a criminal."
According to Gottlieb, Anna is fully aware she has serious problems -- and has already voluntarily entered a treatment center.
Anna has a history of drug issues -- in fact, she was busted back in February 2010 for allegedly stealing her doctor's prescription pad and supplying herself with Rx painkillers ... and her lawyer claims, the shoplifting is just a nasty byproduct of her drug addiction.
Anna -- who was Miss Russia back in 1998 -- was arrested on Tuesday for allegedly pilfering a pair of sandals and a hat from a Manhattan clothing store ... and has since been charged with criminal possession of stolen property and petit larceny.
Anna's due back in court in May for the shoplifting charges.