April 29 (Reuters) - Acadia Pharmaceuticals Inc's drug for psychosis linked to Parkinson's disease was approved by the U.S. Food and Drug Administration on Friday, becoming the first ever treatment to get a U.S. nod for the condition.

The regulator, however, asked Acadia to include a black-box warning, its strictest warning, on the drug's label for an increased risk of death associated with its use in older people.

Analysts have said the warning will have a limited impact on sales as antipsychotics often come with such warnings.

(Reporting by Subrat Patnaik in Bengaluru; Editing by Kirti Pandey)