Nellie Bly was a journalist who immersed herself within what she was writing.  Famously in 1887, she was committed to Blackwell’s Island Insane Asylum for Women after entering a boarding house for working women while claiming she was an immigrant and refusing sleep.  Knowing the stereotypes of immigrants she knew if she claimed this, they would be more likely to be committed. Police were called and she was taken to the asylum. She was in the facility for 10 days, where she witnessed and was subjected to severe beatings, being given spoiled food, little clothing or bedding, being bathed in freezing and unhygienic conditions, and verbal abuse by staff. She also noticed how many of the patients were “normal”.  Several of the women in the facility did not have any mental health issues and were being held anyways. After 10 days of being in the asylum, a male colleague of hers got her discharged (she attempted to tell the staff she was completely fine, however they did not believe her).  After this she wrote 10 Days in a Madhouse, where she exposed the maltreatment of mental health facility patients.

https://www.nyhistory.org/blogs/nellie-blys-ten-days-in-a-mad-house-and-...