MANDEVILLE, La. — Annelle S., 64, who has paranoid schizophrenia, took an urgent drag on a cigarette at a supervised outdoor smoke break at Southeast Louisiana Hospital.

“It’s mandatory to smoke,” she explained. “It’s a mental institution, and we have to smoke by law.”

That was 18 months ago, and Annelle’s confusion was understandable. Until recently, Louisiana law required psychiatric hospitals to accommodate smokers — unlike rules banning smoking at most other health facilities. The law was changed last year, and by March 30, smoking is supposed to end at Louisiana’s two remaining state psychiatric hospitals.

After decades in which smoking by people with mental illness was supported and even encouraged — a legacy that experts say is causing patients to die prematurely from smoking-related illnesses — Louisiana’s move reflects a growing effort by federal, state and other health officials to reverse course.

But these efforts are hardly simple given the longstanding obstacles.

Hospitals often used cigarettes as incentives or rewards for taking medicine, following rules or attending therapy. Some programs still do. And smoking was endorsed by advocates for people with mental illness and family members, who sometimes sued to preserve smoking rights, considering cigarettes one of the few pleasures patients were allowed.